Generic file level restore from a block-level secondary copy

ABSTRACT

Systems and methods are provided which perform a file level restore by utilizing existing operating system components (e.g., file system drivers) that are natively installed on the target computing device. These components can be used to mount and/or interpret a secondary copy of the file system. For instance, the system can instantiate an interface object (e.g., a device node such as a pseudo device, device file or special file) on the target client which includes file system metadata corresponding to the backed up version of the file system. The interface provides a mechanism for the operating system to mount the secondary copy and perform file level access on the secondary copy, e.g., to restore one or more selected files.

This application claims the benefit of priority under 35 U.S.C. §119(e)of U.S. Provisional Application No. 61/682,613 filed on Aug. 13, 2012,and entitled “GENERIC FILE LEVEL RESTORE FROM A BLOCK-LEVEL SECONDARYCOPY”, the entirety of which is incorporated herein by reference. Anyand all priority claims identified in the Application Data Sheet, or anycorrection thereto, are hereby incorporated by reference under 37 CFR1.57.

BACKGROUND

Businesses worldwide recognize the commercial value of their data andseek reliable, cost-effective ways to protect the information stored ontheir computer networks while minimizing impact on productivity.Protecting information is often part of a routine process that isperformed within an organization.

A company might back up critical computing systems such as databases,file servers, web servers, and so on as part of a daily, weekly, ormonthly maintenance schedule. The company may similarly protectcomputing systems used by each of its employees, such as those used byan accounting department, marketing department, engineering department,and so forth.

Given the rapidly expanding volume of data under management, companiesalso continue to seek innovative techniques for managing data growth, inaddition to protecting data. For instance, companies often implementmigration techniques for moving data to lower cost storage over time anddata reduction techniques for reducing redundant data, pruning lowerpriority data, etc.

Enterprises also increasingly view their stored data as a valuableasset. Along these lines, customers are looking for solutions that notonly protect and manage, but also leverage their data. For instance,solutions providing data analysis capabilities, improved datapresentation and access features, and the like, are in increasingdemand.

Given the integral nature of file systems in typical computingenvironments, it is generally important for data protection schemes toprotect file system data (e.g., files and directories, metadata, mountpoints, etc.). Thus, data protection systems often create backups orother secondary copies of file system data.

SUMMARY

File system data can be copied at the file level in some cases, in whicheach file is copied to secondary storage as a complete logical entity.In other cases, the files can be copied at the block-level, in whicheach of the files are divided data blocks (e.g., fixed size data blocks)and copied to secondary storage. Block-level copying can provide certainadvantages. For instance, backing up or otherwise copying at theblock-level can be significantly faster than file-level backups,particularly when the file system is full or nearly full. This isbecause, unlike a file-level backup, the disk is typically readsequentially or substantially sequentially during a block-level backup,without parsing the file system metadata. However, users generally willwant to restore the data at the file level, and restoring data at thefile level from block-level secondary copies can be challenging.

For instance, restoring a particular file to a target computing deviceinvolves identifying the blocks that form the file and locating thoseblocks in secondary storage. But, the secondary copy of the file systemgenerally includes the metadata corresponding to the directory structurewhich is file system type specific, and restoring the file wouldtypically require knowledge of the internal file system layout toreconstruct the files.

In some cases, specialized code can be used to parse through the dataduring the backup process to create a traversable map of the backed upversion of the file system. This map could be stored in a cache or onsecondary storage along with the secondary copy. On restore, the systemaccesses the pre-existing map and uses it to mount and/or traversethrough the file system hierarchy. In this manner, the system can locatefiles being restored, their constituent data blocks, and the locationsof the data blocks in secondary storage.

In such a scheme, the specialized code implements logic that is basedthe specification of the file system, and is therefore specificallytailored to the particular type and/or version of the file system beingprotected. Particularly where multiple file system types and/or versionsare supported by the data storage system, developing and maintainingsuch specialized modules for interpreting each file system type and/orversion can become burdensome.

Thus, according to some embodiments, systems and methods are providedwhich perform a file level restore by utilizing existing operatingsystem components (e.g., file system drivers) that are nativelyinstalled on the target computing device. These components are used tomount and/or interpret the backed up version of the file system.

For instance, in some embodiments the system instantiates an interfaceobject (e.g., device node such as a pseudo device, device file orspecial file) on the target client which includes file system metadata(e.g., block size information, inode table location or other informationrelated to inode tables, a block map, block group information, etc.)corresponding to the backed up version of the file system. The interfaceprovides a mechanism for the operating system to mount the secondarycopy and perform file level access on the secondary copy, e.g., torestore one or more selected files.

As one example, the system instructs the operating system on the targetclient (also referred to as a “destination client”) to mount orotherwise process the interface object. As part of this process, theoperating system obtains and processes the file system metadata, selectsthe appropriate file system driver, and instructs that driver to performthe mount. The metadata is generally sufficient to allow the nativeoperating system components to mount the secondary copy. The user canselect one or more files to restore by browsing the mounted version ofthe file system represented by the mounted secondary copy. To restorethe requested files, the file system drivers can interact with thedevice interface to process the file system metadata and identify andrequest the constituent blocks that form the selected files. Theinterface services the block requests by obtaining the requested blocksfrom secondary storage. The target client processes the received blocksto reconstitute the requested files and restore them to primary storage.

DESCRIPTION OF THE DRAWINGS

FIG. 1A is a block diagram illustrating an exemplary informationmanagement system.

FIG. 1B is a detailed view of a primary storage device, a secondarystorage device, and some examples of primary data and secondary copydata.

FIG. 1C is a block diagram of an exemplary information management systemincluding a storage manager, one or more data agents, and one or moremedia agents.

FIG. 1D is a block diagram illustrating a scalable informationmanagement system.

FIG. 1E illustrates certain secondary copy operations according to anexemplary storage policy.

FIG. 2 shows a portion of an example data storage system configured toprovide file level restore capability from a block level secondary copy.

FIG. 3 is a flowchart illustrating an example routine for performing afile level restore from a block level secondary copy.

DETAILED DESCRIPTION

Systems and methods are described herein for performing a file levelrestore from a block level secondary copy. Examples of such systems andmethods are discussed in further detail herein, e.g., with respect toFIGS. 2-3. Moreover, it will be appreciated that the file level restoretechniques described herein may be performed by information managementsystems such as those that will now be described with respect to FIGS.1A-1E. And, the componentry for implementing file level restorefunctionality can be incorporated into such systems.

Information Management System Overview

With the increasing importance of protecting and leveraging data,organizations simply cannot afford to take the risk of losing criticaldata. Moreover, runaway data growth and other modern realities makeprotecting and managing data an increasingly difficult task. There istherefore a need for efficient, powerful, and user-friendly solutionsfor protecting and managing data.

Depending on the size of the organization, there are typically many dataproduction sources which are under the purview of tens, hundreds, oreven thousands of employees or other individuals. In the past,individual employees were sometimes responsible for managing andprotecting their data. A patchwork of hardware and software pointsolutions have been applied in other cases. These solutions were oftenprovided by different vendors and had limited or no interoperability.

Certain embodiments described herein provide systems and methods capableof addressing these and other shortcomings of prior approaches byimplementing unified, organization-wide information management. FIG. 1Ashows one such information management system 100, which generallyincludes combinations of hardware and software configured to protect andmanage data and metadata generated and used by the various computingdevices in the information management system 100.

The organization which employs the information management system 100 maybe a corporation or other business entity, non-profit organization,educational institution, household, governmental agency, or the like.

Generally, the systems and associated components described herein may becompatible with and/or provide some or all of the functionality of thesystems and corresponding components described in one or more of thefollowing U.S. patents and patent application publications assigned toCommVault Systems, Inc., each of which is hereby incorporated in itsentirety by reference herein:

-   -   U.S. Pat. Pub. No. 2010-0332456, entitled “DATA OBJECT STORE AND        SERVER FOR A CLOUD STORAGE ENVIRONMENT, INCLUDING DATA        DEDUPLICATION AND DATA MANAGEMENT ACROSS MULTIPLE CLOUD STORAGE        SITES”;    -   U.S. Pat. No. 7,035,880, entitled “MODULAR BACKUP AND RETRIEVAL        SYSTEM USED IN CONJUNCTION WITH A STORAGE AREA NETWORK”;    -   U.S. Pat. No. 7,343,453, entitled “HIERARCHICAL SYSTEMS AND        METHODS FOR PROVIDING A UNIFIED VIEW OF STORAGE INFORMATION”;    -   U.S. Pat. No. 7,395,282, entitled “HIERARCHICAL BACKUP AND        RETRIEVAL SYSTEM”;    -   U.S. Pat. No. 7,246,207, entitled “SYSTEM AND METHOD FOR        DYNAMICALLY PERFORMING STORAGE OPERATIONS IN A COMPUTER        NETWORK”;    -   U.S. Pat. No. 7,747,579, entitled “METABASE FOR FACILITATING        DATA CLASSIFICATION”;    -   U.S. Pat. No. 8,229,954, entitled “MANAGING COPIES OF DATA”;    -   U.S. Pat. No. 7,617,262, entitled “SYSTEM AND METHODS FOR        MONITORING APPLICATION DATA IN A DATA REPLICATION SYSTEM”;    -   U.S. Pat. No. 7,529,782, entitled “SYSTEM AND METHODS FOR        PERFORMING A SNAPSHOT AND FOR RESTORING DATA”;    -   U.S. Pat. No. 8,230,195, entitled “SYSTEM AND METHOD FOR        PERFORMING AUXILIARY STORAGE OPERATIONS”;    -   U.S. Pat. No. 8,364,652, entitled “CONTENT-ALIGNED, BLOCK-BASED        DEDUPLICATION”;    -   U.S. Pat. Pub. No. 2006/0224846, entitled “SYSTEM AND METHOD TO        SUPPORT SINGLE INSTANCE STORAGE OPERATIONS”;    -   U.S. Pat. Pub. No. 2009/0329534, entitled “APPLICATION-AWARE AND        REMOTE SINGLE INSTANCE DATA MANAGEMENT”;    -   U.S. Pat. Pub. No. 2012/0150826, entitled “DISTRIBUTED        DEDUPLICATED STORAGE SYSTEM”;    -   U.S. Pat. Pub. No. 2012/0150818, entitled “CLIENT-SIDE        REPOSITORY IN A NETWORKED DEDUPLICATED STORAGE SYSTEM”;    -   U.S. Pat. No. 8,170,995, entitled “METHOD AND SYSTEM FOR OFFLINE        INDEXING OF CONTENT AND CLASSIFYING STORED DATA”; and    -   U.S. Pat. No. 8,156,086, entitled “SYSTEMS AND METHODS FOR        STORED DATA VERIFICATION”.

The illustrated information management system 100 includes one or moreclient computing device 102 having at least one application 110executing thereon, and one or more primary storage devices 104 storingprimary data 112. The client computing device(s) 102 and the primarystorage devices 104 may generally be referred to in some cases as aprimary storage subsystem 117.

Depending on the context, the term “information management system” canrefer to generally all of the illustrated hardware and softwarecomponents. Or, in other instances, the term may refer to only a subsetof the illustrated components.

For instance, in some cases information management system 100 generallyrefers to a combination of specialized components used to protect, move,manage, manipulate and/or process data and metadata generated by theclient computing devices 102. However, the term may generally not referto the underlying components that generate and/or store the primary data112, such as the client computing devices 102 themselves, theapplications 110 and operating system residing on the client computingdevices 102, and the primary storage devices 104.

As an example, “information management system” may sometimes refer onlyto one or more of the following components and corresponding datastructures: storage managers, data agents, and media agents. Thesecomponents will be described in further detail below.

Client Computing Devices

There are typically a variety of sources in an organization that producedata to be protected and managed. As just one illustrative example, in acorporate environment such data sources can be employee workstations andcompany servers such as a mail server, a web server, or the like. In theinformation management system 100, the data generation sources includethe one or more client computing devices 102.

The client computing devices 102 may include, without limitation, one ormore: workstations, personal computers, desktop computers, or othertypes of generally fixed computing systems such as mainframe computersand minicomputers.

The client computing devices 102 can also include mobile or portablecomputing devices, such as one or more laptops, tablet computers,personal data assistants, mobile phones (such as smartphones), and othermobile or portable computing devices such as embedded computers, set topboxes, vehicle-mounted devices, wearable computers, etc.

In some cases, each client computing device 102 is associated with oneor more users and/or corresponding user accounts, of employees or otherindividuals.

The term “client computing device” is used herein because theinformation management system 100 generally “serves” the data managementand protection needs for the data generated by the client computingdevices 102. However, the use of this term does not imply that theclient computing devices 102 cannot be “servers” in other respects. Forinstance, a particular client computing device 102 may act as a serverwith respect to other devices, such as other client computing devices102. As just a few examples, the client computing devices 102 caninclude mail servers, file servers, database servers, and web servers.

The client computing devices 102 may additionally include virtualizedand/or cloud computing resources. For instance, one or more virtualmachines may be provided to the organization by a third-party cloudservice vendor. Or, in some embodiments, the client computing devices102 include one or more virtual machine(s) running on a virtual machinehost computing device operated by the organization. As one example, theorganization may use one virtual machine as a database server andanother virtual machine as a mail server. A virtual machine manager(VMM) (e.g., a Hypervisor) may manage the virtual machines, and resideand execute on the virtual machine host computing device.

Each client computing device 102 may have one or more applications 110(e.g., software applications) executing thereon which generate andmanipulate the data that is to be protected from loss.

The applications 110 generally facilitate the operations of anorganization (or multiple affiliated organizations), and can include,without limitation, mail server applications (e.g., Microsoft ExchangeServer), file server applications, mail client applications (e.g.,Microsoft Exchange Client), database applications (e.g., SQL, Oracle,SAP, Lotus Notes Database), word processing applications (e.g.,Microsoft Word), spreadsheet applications, financial applications,presentation applications, browser applications, mobile applications,entertainment applications, and so on.

The applications 110 can include at least one operating system (e.g.,Microsoft Windows, Mac OS X, iOS, IBM z/OS, Linux, other Unix-basedoperating systems, etc.), which may support one or more file systems andhost the other applications 110.

As shown, the client computing devices 102 and other components in theinformation management system 100 can be connected to one another viaone or more communication pathways 114. The communication pathways 114can include one or more networks or other connection types including asany of following, without limitation: the Internet, a wide area network(WAN), a local area network (LAN), a Storage Area Network (SAN), a FibreChannel connection, a Small Computer System Interface (SCSI) connection,a virtual private network (VPN), a token ring or TCP/IP based network,an intranet network, a point-to-point link, a cellular network, awireless data transmission system, a two-way cable system, aninteractive kiosk network, a satellite network, a broadband network, abaseband network, other appropriate wired, wireless, or partiallywired/wireless computer or telecommunications networks, combinations ofthe same or the like. The communication pathways 114 in some cases mayalso include application programming interfaces (APIs) including, e.g.,cloud service provider APIs, virtual machine management APIs, and hostedservice provider APIs.

Primary Data and Exemplary Primary Storage Devices

Primary data 112 according to some embodiments is production data orother “live” data generated by the operating system and otherapplications 110 residing on a client computing device 102. The primarydata 112 is stored on the primary storage device(s) 104 and is organizedvia a file system supported by the client computing device 102. Forinstance, the client computing device(s) 102 and correspondingapplications 110 may create, access, modify, write, delete, andotherwise use primary data 112.

Primary data 112 is generally in the native format of the sourceapplication 110. According to certain aspects, primary data 112 is aninitial or first (e.g., created before any other copies or before atleast one other copy) stored copy of data generated by the sourceapplication 110. Primary data 112 in some cases is created substantiallydirectly from data generated by the corresponding source applications110.

The primary data 112 may sometimes be referred to as a “primary copy” inthe sense that it is a discrete set of data. However, the use of thisterm does not necessarily imply that the “primary copy” is a copy in thesense that it was copied or otherwise derived from another storedversion.

The primary storage devices 104 storing the primary data 112 may berelatively fast and/or expensive (e.g., a disk drive, a hard-disk array,solid state memory, etc.). In addition, primary data 112 may be intendedfor relatively short term retention (e.g., several hours, days, orweeks).

According to some embodiments, the client computing device 102 canaccess primary data 112 from the primary storage device 104 by makingconventional file system calls via the operating system. Primary data112 representing files may include structured data (e.g., databasefiles), unstructured data (e.g., documents), and/or semi-structureddata. Some specific examples are described below with respect to FIG.1B.

It can be useful in performing certain tasks to break the primary data112 up into units of different granularities. In general, primary data112 can include files, directories, file system volumes, data blocks,extents, or any other types or granularities of data objects. As usedherein, a “data object” can refer to both (1) any file that is currentlyaddressable by a file system or that was previously addressable by thefile system (e.g., an archive file) and (2) a subset of such a file.

As will be described in further detail, it can also be useful inperforming certain functions of the information management system 100 toaccess and modify metadata within the primary data 112. Metadatagenerally includes information about data objects or characteristicsassociated with the data objects.

Metadata can include, without limitation, one or more of the following:the data owner (e.g., the client or user that generates the data), thelast modified time (e.g., the time of the most recent modification ofthe data object), a data object name (e.g., a file name), a data objectsize (e.g., a number of bytes of data), information about the content(e.g., an indication as to the existence of a particular search term),to/from information for email (e.g., an email sender, recipient, etc.),creation date, file type (e.g., format or application type), lastaccessed time, application type (e.g., type of application thatgenerated the data object), location/network (e.g., a current, past orfuture location of the data object and network pathways to/from the dataobject), frequency of change (e.g., a period in which the data object ismodified), business unit (e.g., a group or department that generates,manages or is otherwise associated with the data object), and aginginformation (e.g., a schedule, such as a time period, in which the dataobject is migrated to secondary or long term storage), boot sectors,partition layouts, file location within a file folder directorystructure, user permissions, owners, groups, access control lists[ACLS]), system metadata (e.g., registry information), combinations ofthe same or the like.

In addition to metadata generated by or related to file systems andoperating systems, some of the applications 110 maintain indices ofmetadata for data objects, e.g., metadata associated with individualemail messages. Thus, each data object may be associated withcorresponding metadata. The use of metadata to perform classificationand other functions is described in greater detail below.

Each of the client computing devices 102 are associated with and/or incommunication with one or more of the primary storage devices 104storing corresponding primary data 112. A client computing device 102may be considered to be “associated with” or “in communication with” aprimary storage device 104 if it is capable of one or more of: storingdata to the primary storage device 104, retrieving data from the primarystorage device 104, and modifying data retrieved from a primary storagedevice 104.

The primary storage devices 104 can include, without limitation, diskdrives, hard-disk arrays, semiconductor memory (e.g., solid statedrives), and network attached storage (NAS) devices. In some cases, theprimary storage devices 104 form part of a distributed file system. Theprimary storage devices 104 may have relatively fast I/O times and/orare relatively expensive in comparison to the secondary storage devices108. For example, the information management system 100 may generallyregularly access data and metadata stored on primary storage devices104, whereas data and metadata stored on the secondary storage devices108 is accessed relatively less frequently.

In some cases, each primary storage device 104 is dedicated to anassociated client computing devices 102. For instance, a primary storagedevice 104 in one embodiment is a local disk drive of a correspondingclient computing device 102. In other cases, one or more primary storagedevices 104 can be shared by multiple client computing devices 102. Asone example, a primary storage device 104 can be a disk array shared bya group of client computing devices 102, such as one of the followingtypes of disk arrays: EMC Clariion, EMC Symmetrix, EMC Celerra, DellEqualLogic, IBM XIV, NetApp FAS, HP EVA, and HP 3PAR.

The information management system 100 may also include hosted services(not shown), which may be hosted in some cases by an entity other thanthe organization that employs the other components of the informationmanagement system 100. For instance, the hosted services may be providedby various online service providers to the organization. Such serviceproviders can provide services including social networking services,hosted email services, or hosted productivity applications or otherhosted applications).

Hosted services may include software-as-a-service (SaaS),platform-as-a-service (PaaS), application service providers (ASPS),cloud services, or other mechanisms for delivering functionality via anetwork. As it provides services to users, each hosted service maygenerate additional data and metadata under management of theinformation management system 100, e.g., as primary data 112. In somecases, the hosted services may be accessed using one of the applications110. As an example, a hosted mail service may be accessed via browserrunning on a client computing device 102.

Secondary Copies and Exemplary Secondary Storage Devices

The primary data 112 stored on the primary storage devices 104 may becompromised in some cases, such as when an employee deliberately oraccidentally deletes or overwrites primary data 112 during their normalcourse of work. Or the primary storage devices 104 can be damaged orotherwise corrupted.

For recovery and/or regulatory compliance purposes, it is thereforeuseful to generate copies of the primary data 112. Accordingly, theinformation management system 100 includes one or more secondary storagecomputing devices 106 and one or more secondary storage devices 108configured to create and store one or more secondary copies 116 of theprimary data 112 and associated metadata. The secondary storagecomputing devices 106 and the secondary storage devices 108 may bereferred to in some cases as a secondary storage subsystem 118.

Creation of secondary copies 116 can help meet information managementgoals, such as: restoring data and/or metadata if an original version(e.g., of primary data 112) is lost (e.g., by deletion, corruption, ordisaster); allowing point-in-time recovery; complying with regulatorydata retention and electronic discovery (e-discovery) requirements;reducing utilized storage capacity; facilitating organization and searchof data; improving user access to data files across multiple computingdevices and/or hosted services; and implementing data retentionpolicies.

Types of secondary copy operations can include, without limitation,backup operations, archive operations, snapshot operations, replicationoperations (e.g., continuous data replication [CDR]), data retentionpolicies such as information lifecycle management and hierarchicalstorage management operations, and the like. These specific typesoperations are discussed in greater detail below.

Regardless of the type of secondary copy operation, the client computingdevices 102 access or receive primary data 112 and communicate the data,e.g., over the communication pathways 114, for storage in the secondarystorage device(s) 108.

A secondary copy 116 can comprise a separate stored copy of applicationdata that is derived from one or more earlier created, stored copies(e.g., derived from primary data 112 or another secondary copy 116).Secondary copies 116 can include point-in-time data, and may be intendedfor relatively long-term retention (e.g., weeks, months or years),before some or all of the data is moved to other storage or isdiscarded.

In some cases, a secondary copy 116 is a copy of application datacreated and stored subsequent to at least one other stored instance(e.g., subsequent to corresponding primary data 112 or to anothersecondary copy 116), in a different storage device than at least oneprevious stored copy, and/or remotely from at least one previous storedcopy. Secondary copies 116 may be stored in relatively slow and/or lowcost storage (e.g., magnetic tape). A secondary copy 116 may be storedin a backup or archive format, or in some other format different thanthe native source application format or other primary data format.

In some cases, secondary copies 116 are indexed so users can browse andrestore at another point in time. After creation of a secondary copy 116representative of certain primary data 112, a pointer or other locationindicia (e.g., a stub) may be placed in primary data 112, or beotherwise associated with primary data 112 to indicate the currentlocation on the secondary storage device(s) 108.

Since an instance a data object or metadata in primary data 112 maychange over time as it is modified by an application 110 (or hostedservice or the operating system), the information management system 100may create and manage multiple secondary copies 116 of a particular dataobject or metadata, each representing the state of the data object inprimary data 112 at a particular point in time. Moreover, since aninstance of a data object in primary data 112 may eventually be deletedfrom the primary storage device 104 and the file system, the informationmanagement system 100 may continue to manage point-in-timerepresentations of that data object, even though the instance in primarydata 112 no longer exists.

For virtualized computing devices the operating system and otherapplications 110 of the client computing device(s) 102 may executewithin or under the management of virtualization software (e.g., a VMM),and the primary storage device(s) 104 may comprise a virtual diskcreated on a physical storage device. The information management system100 may create secondary copies 116 of the files or other data objectsin a virtual disk file and/or secondary copies 116 of the entire virtualdisk file itself (e.g., of an entire .vmdk file).

Secondary copies 116 may be distinguished from corresponding primarydata 112 in a variety of ways, some of which will now be described.First, as discussed, secondary copies 116 can be stored in a differentformat (e.g., backup, archive, or other non-native format) than primarydata 112. For this or other reasons, secondary copies 116 may not bedirectly useable by the applications 110 of the client computing device102, e.g., via standard system calls or otherwise without modification,processing, or other intervention by the information management system100.

Secondary copies 116 are also often stored on a secondary storage device108 that is inaccessible to the applications 110 running on the clientcomputing devices 102 (and/or hosted services). Some secondary copies116 may be “offline copies,” in that they are not readily available(e.g. not mounted to tape or disk). Offline copies can include copies ofdata that the information management system 100 can access without humanintervention (e.g. tapes within an automated tape library, but not yetmounted in a drive), and copies that the information management system100 can access only with at least some human intervention (e.g. tapeslocated at an offsite storage site).

The secondary storage devices 108 can include any suitable type ofstorage device such as, without limitation, one or more tape libraries,disk drives or other magnetic, non-tape storage devices, optical mediastorage devices, solid state storage devices, NAS devices, combinationsof the same, and the like. In some cases, the secondary storage devices108 are provided in a cloud (e.g. a private cloud or one operated by athird-party vendor).

The secondary storage device(s) 108 in some cases comprises a disk arrayor a portion thereof. In some cases, a single storage device (e.g., adisk array) is used for storing both primary data 112 and at least somesecondary copies 116. In one example, a disk array capable of performinghardware snapshots stores primary data 112 and creates and storeshardware snapshots of the primary data 112 as secondary copies 116.

The Use of Intermediary Devices for Creating Secondary Copies

Creating secondary copies can be a challenging task. For instance, therecan be hundreds or thousands of client computing devices 102 continuallygenerating large volumes of primary data 112 to be protected. Also,there can be significant overhead involved in the creation of secondarycopies 116. Moreover, secondary storage devices 108 may be specialpurpose components, and interacting with them can require specializedintelligence.

In some cases, the client computing devices 102 interact directly withthe secondary storage device 108 to create the secondary copies 116.However, in view of the factors described above, this approach cannegatively impact the ability of the client computing devices 102 toserve the applications 110 and produce primary data 112. Further, theclient computing devices 102 may not be optimized for interaction withthe secondary storage devices 108.

Thus, in some embodiments, the information management system 100includes one or more software and/or hardware components which generallyact as intermediaries between the client computing devices 102 and thesecondary storage devices 108. In addition to off-loading certainresponsibilities from the client computing devices 102, theseintermediary components can provide other benefits. For instance, asdiscussed further below with respect to FIG. 1D, distributing some ofthe work involved in creating secondary copies 116 can enhancescalability.

The intermediary components can include one or more secondary storagecomputing devices 106 as shown in FIG. 1A and/or one or more mediaagents, which can be software modules residing on correspondingsecondary storage computing devices 106 (or other appropriate devices).Media agents are discussed below (e.g., with respect to FIGS. 1C-1E).

The secondary storage computing device(s) 106 can comprise anyappropriate type of computing device and can include, withoutlimitation, any of the types of fixed and portable computing devicesdescribed above with respect to the client computing devices 102. Insome cases, the secondary storage computing device(s) 106 includespecialized hardware and/or software componentry for interacting withthe secondary storage devices 108.

To create a secondary copy 116, the client computing device 102communicates the primary data 112 to be copied (or a processed versionthereof) to the designated secondary storage computing device 106, viathe communication pathway 114. The secondary storage computing device106 in turn conveys the received data (or a processed version thereof)to the secondary storage device 108. In some such configurations, thecommunication pathway 114 between the client computing device 102 andthe secondary storage computing device 106 comprises a portion of a LAN,WAN or SAN. In other cases, at least some client computing devices 102communicate directly with the secondary storage devices 108 (e.g., viaFibre Channel or SCSI connections).

Exemplary Primary Data and an Exemplary Secondary Copy

FIG. 1B is a detailed view showing some specific examples of primarydata stored on the primary storage device(s) 104 and secondary copy datastored on the secondary storage device(s) 108, with other components inthe system removed for the purposes of illustration. Stored on theprimary storage device(s) 104 are primary data objects including wordprocessing documents 119A-B, spreadsheets 120, presentation documents122, video files 124, image files 126, email mailboxes 128 (andcorresponding email messages 129A-C), html/xml or other types of markuplanguage files 130, databases 132 and corresponding tables 133A-133C).

Some or all primary data objects are associated with a primary copy ofobject metadata (e.g., “Meta1-11”), which may be file system metadataand/or application specific metadata. Stored on the secondary storagedevice(s) 108 are secondary copy objects 134A-C which may include copiesof or otherwise represent corresponding primary data objects andmetadata.

As shown, the secondary copy objects 134A-C can individually representmore than one primary data object. For example, secondary copy dataobject 134A represents three separate primary data objects 133C, 122 and129C (represented as 133C′, 122′ and 129C′, respectively). Moreover, asindicated by the prime mark (′), a secondary copy object may store arepresentation of a primary data object or metadata differently than theoriginal format, e.g., in a compressed, encrypted, deduplicated, orother modified format.

Exemplary Information Management System Architecture

The information management system 100 can incorporate a variety ofdifferent hardware and software components, which can in turn beorganized with respect to one another in many different configurations,depending on the embodiment. There are critical design choices involvedin specifying the functional responsibilities of the components and therole of each component in the information management system 100. Forinstance, as will be discussed, such design choices can impactperformance as well as the adaptability of the information managementsystem 100 to data growth or other changing circumstances.

FIG. 1C shows an information management system 100 designed according tothese considerations and which includes: a central storage orinformation manager 140 configured to perform certain control functions,one or more data agents 142 executing on the client computing device(s)102 configured to process primary data 112, and one or more media agents144 executing on the one or more secondary storage computing devices 106for performing tasks involving the secondary storage devices 108.

Storage Manager

As noted, the number of components in the information management system100 and the amount of data under management can be quite large. Managingthe components and data is therefore a significant task, and a task thatcan grow in an often unpredictable fashion as the quantity of componentsand data scale to meet the needs of the organization.

For these and other reasons, according to certain embodiments,responsibility for controlling the information management system 100, orat least a significant portion of that responsibility, is allocated tothe storage manager 140.

By distributing control functionality in this manner, the storagemanager 140 can be adapted independently according to changingcircumstances. Moreover, a host computing device can be selected to bestsuit the functions of the storage manager 140. These and otheradvantages are described in further detail below with respect to FIG.1D.

The storage manager 140 may be a software module or other application.The storage manager generally initiates, coordinates and/or controlsstorage and other information management operations performed by theinformation management system 100, e.g., to protect and control theprimary data 112 and secondary copies 116 of data and metadata.

As shown by the dashed, arrowed lines, the storage manager 140 maycommunicate with and/or control some or all elements of the informationmanagement system 100, such as the data agents 142 and media agents 144.Thus, in certain embodiments, control information originates from thestorage manager 140, whereas payload data and metadata is generallycommunicated between the data agents 142 and the media agents 144 (orotherwise between the client computing device(s) 102 and the secondarystorage computing device(s) 106), e.g., at the direction of the storagemanager 140. In other embodiments, some information managementoperations are controlled by other components in the informationmanagement system 100 (e.g., the media agent(s) 144 or data agent(s)142), instead of or in combination with the storage manager 140.

According to certain embodiments, the storage manager provides one ormore of the following functions:

-   -   initiating execution of secondary copy operations;    -   managing secondary storage devices 108 and inventory/capacity of        the same;    -   allocating secondary storage devices 108 for secondary storage        operations;    -   monitoring completion of and providing status reporting related        to secondary storage operations;    -   tracking age information relating to secondary copies 116,        secondary storage devices 108, and comparing the age information        against retention guidelines;    -   tracking movement of data within the information management        system 100;    -   tracking logical associations between components in the        information management system 100;    -   protecting metadata associated with the information management        system 100; and    -   implementing operations management functionality.

The storage manager 140 may maintain a database 146 ofmanagement-related data and information management policies 148. Thedatabase 146 may include a management index 150 or other data structurethat stores logical associations between components of the system, userpreferences and/or profiles (e.g., preferences regarding encryption,compression, or deduplication of primary or secondary copy data,preferences regarding the scheduling, type, or other aspects of primaryor secondary copy or other operations, mappings of particularinformation management users or user accounts to certain computingdevices or other components, etc.), management tasks, mediacontainerization, or other useful data. For example, the storage manager140 may use the index 150 to track logical associations between mediaagents 144 and secondary storage devices 108 and/or movement of datafrom primary storage devices 104 to secondary storage devices 108.

Administrators and other employees may be able to manually configure andinitiate certain information management operations on an individualbasis. But while this may be acceptable for some recovery operations orother relatively less frequent tasks, it is often not workable forimplementing on-going organization-wide data protection and management.

Thus, the information management system 100 may utilize informationmanagement policies 148 for specifying and executing informationmanagement operations (e.g., on an automated basis). Generally, aninformation management policy 148 can include a data structure or otherinformation source that specifies a set of parameters (e.g., criteriaand rules) associated with storage or other information managementoperations.

The storage manager database 146 may maintain the information managementpolicies 148 and associated data, although the information managementpolicies 148 can be stored in any appropriate location. For instance, astorage policy may be stored as metadata in a media agent database 152or in a secondary storage device 108 (e.g., as an archive copy) for usein restore operations or other information management operations,depending on the embodiment. Information management policies 148 aredescribed further below.

According to certain embodiments, the storage manager database 146comprises a relational database (e.g., an SQL database) for trackingmetadata, such as metadata associated with secondary copy operations(e.g., what client computing devices 102 and corresponding data wereprotected). This and other metadata may additionally be stored in otherlocations, such as at the secondary storage computing devices 106 or onthe secondary storage devices 108, allowing data recovery without theuse of the storage manager 140.

As shown, the storage manager 140 may include a jobs agent 156, a userinterface 158, and a management agent 154, all of which may beimplemented as interconnected software modules or application programs.

The jobs agent 156 in some embodiments initiates, controls, and/ormonitors the status of some or all storage or other informationmanagement operations previously performed, currently being performed,or scheduled to be performed by the information management system 100.For instance, the jobs agent 156 may access information managementpolicies 148 to determine when and how to initiate and control secondarycopy and other information management operations, as will be discussedfurther.

The user interface 158 may include information processing and displaysoftware, such as a graphical user interface (“GUI”), an applicationprogram interface (“API”), or other interactive interface through whichusers and system processes can retrieve information about the status ofinformation management operations (e.g., storage operations) or issueinstructions to the information management system 100 and itsconstituent components.

The storage manager 140 may also track information that permits it toselect, designate, or otherwise identify content indices, deduplicationdatabases, or similar databases or resources or data sets within itsinformation management cell (or another cell) to be searched in responseto certain queries. Such queries may be entered by the user viainteraction with the user interface 158.

Via the user interface 158, users may optionally issue instructions tothe components in the information management system 100 regardingperformance of storage and recovery operations. For example, a user maymodify a schedule concerning the number of pending secondary copyoperations. As another example, a user may employ the GUI to view thestatus of pending storage operations or to monitor the status of certaincomponents in the information management system 100 (e.g., the amount ofcapacity left in a storage device).

In general, the management agent 154 allows multiple informationmanagement systems 100 to communicate with one another. For example, theinformation management system 100 in some cases may be one informationmanagement subsystem or “cell” of a network of multiple cells adjacentto one another or otherwise logically related in a WAN or LAN. With thisarrangement, the cells may be connected to one another throughrespective management agents 154.

For instance, the management agent 154 can provide the storage manager140 with the ability to communicate with other components within theinformation management system 100 (and/or other cells within a largerinformation management system) via network protocols and applicationprogramming interfaces (“APIs”) including, e.g., HTTP, HTTPS, FTP, REST,virtualization software APIs, cloud service provider APIs, and hostedservice provider APIs. Inter-cell communication and hierarchy isdescribed in greater detail in U.S. Pat. No. 7,035,880, which isincorporated by reference herein.

Data Agents

As discussed, a variety of different types of applications 110 canreside on a given client computing device 102, including operatingsystems, database applications, e-mail applications, and virtualmachines, just to name a few. And, as part of the as part of the processof creating and restoring secondary copies 116, the client computingdevices 102 may be tasked with processing and preparing the primary data112 from these various different applications 110. Moreover, the natureof the processing/preparation can differ across clients and applicationtypes, e.g., due to inherent structural and formatting differencesbetween applications 110.

The one or more data agent(s) 142 are therefore advantageouslyconfigured in some embodiments to assist in the performance ofinformation management operations based on the type of data that isbeing protected, at a client-specific and/or application-specific level.

The data agent 142 may be a software module or component that isgenerally responsible for managing, initiating, or otherwise assistingin the performance of information management operations. For instance,the data agent 142 may take part in performing data storage operationssuch as the copying, archiving, migrating, replicating of primary data112 stored in the primary storage device(s) 104. The data agent 142 mayreceive control information from the storage manager 140, such ascommands to transfer copies of data objects, metadata, and other payloaddata to the media agents 144.

In some embodiments, a data agent 142 may be distributed between theclient computing device 102 and storage manager 140 (and any otherintermediate components) or may be deployed from a remote location orits functions approximated by a remote process that performs some or allof the functions of data agent 142. In addition, a data agent 142 mayperform some functions provided by a media agent 144, e.g., encryptionand deduplication.

As indicated, each data agent 142 may be specialized for a particularapplication 110, and the system can employ multiple data agents 142,each of which may backup, migrate, and recover data associated with adifferent application 110. For instance, different individual dataagents 142 may be designed to handle Microsoft Exchange data, LotusNotes data, Microsoft Windows file system data, Microsoft ActiveDirectory Objects data, SQL Server data, SharePoint data, Oracledatabase data, SAP database data, virtual machines and/or associateddata, and other types of data.

A file system data agent, for example, may handle data files and/orother file system information. If a client computing device 102 has twoor more types of data, one data agent 142 may be used for each data typeto copy, archive, migrate, and restore the client computing device 102data. For example, to backup, migrate, and restore all of the data on aMicrosoft Exchange server, the client computing device 102 may use oneMicrosoft Exchange Mailbox data agent 142 to backup the Exchangemailboxes, one Microsoft Exchange Database data agent 142 to backup theExchange databases, one Microsoft Exchange Public Folder data agent 142to backup the Exchange Public Folders, and one Microsoft Windows FileSystem data agent 142 to backup the file system of the client computingdevice 102. In such embodiments, these data agents 142 may be treated asfour separate data agents 142 even though they reside on the same clientcomputing device 102.

Other embodiments may employ one or more generic data agents 142 thatcan handle and process data from two or more different applications 110,or that can handle and process multiple data types, instead of or inaddition to using specialized data agents 142. For example, one genericdata agent 142 may be used to back up, migrate and restore MicrosoftExchange Mailbox data and Microsoft Exchange Database data while anothergeneric data agent may handle Microsoft Exchange Public Folder data andMicrosoft Windows File System data.

Each data agent 142 may be configured to access data and/or metadatastored in the primary storage device(s) 104 associated with the dataagent 142 and process the data as appropriate. For example, during asecondary copy operation, the data agent 142 may arrange or assemble thedata and metadata into one or more files having a certain format (e.g.,a particular backup or archive format) before transferring the file(s)to a media agent 144 or other component. The file(s) may include a listof files or other metadata. Each data agent 142 can also assist inrestoring data or metadata to primary storage devices 104 from asecondary copy 116. For instance, the data agent 142 may operate inconjunction with the storage manager 140 and one or more of the mediaagents 144 to restore data from secondary storage device(s) 108.

Media Agents

As indicated above with respect to FIG. 1A, off-loading certainresponsibilities from the client computing devices 102 to intermediarycomponents such as the media agent(s) 144 can provide a number ofbenefits including improved client computing device 102 operation,faster secondary copy operation performance, and enhanced scalability.As one specific example which will be discussed below in further detail,the media agent 144 can act as a local cache of copied data and/ormetadata that it has stored to the secondary storage device(s) 108,providing improved restore capabilities.

Generally speaking, a media agent 144 may be implemented as a softwaremodule that manages, coordinates, and facilitates the transmission ofdata, as directed by the storage manager 140, between a client computingdevice 102 and one or more secondary storage devices 108. Whereas thestorage manager 140 controls the operation of the information managementsystem 100, the media agent 144 generally provides a portal to secondarystorage devices 108.

Media agents 144 can comprise logically and/or physically separate nodesin the information management system 100 (e.g., separate from the clientcomputing devices 102, storage manager 140, and/or secondary storagedevices 108). In addition, each media agent 144 may reside on adedicated secondary storage computing device 106 in some cases, while inother embodiments a plurality of media agents 144 reside on the samesecondary storage computing device 106.

A media agent 144 (and corresponding media agent database 152) may beconsidered to be “associated with” a particular secondary storage device108 if that media agent 144 is capable of one or more of: routing and/orstoring data to the particular secondary storage device 108,coordinating the routing and/or storing of data to the particularsecondary storage device 108, retrieving data from the particularsecondary storage device 108, and coordinating the retrieval of datafrom a particular secondary storage device 108.

While media agent(s) 144 are generally associated with one or moresecondary storage devices 108, the media agents 144 in certainembodiments are physically separate from the secondary storage devices108. For instance, the media agents 144 may reside on secondary storagecomputing devices 106 having different housings or packages than thesecondary storage devices 108. In one example, a media agent 144 resideson a first server computer and is in communication with a secondarystorage device(s) 108 residing in a separate, rack-mounted RAID-basedsystem.

In operation, a media agent 144 associated with a particular secondarystorage device 108 may instruct the secondary storage device 108 (e.g.,a tape library) to use a robotic arm or other retrieval means to load oreject a certain storage media, and to subsequently archive, migrate, orretrieve data to or from that media, e.g., for the purpose of restoringthe data to a client computing device 102. The media agent 144 maycommunicate with a secondary storage device 108 via a suitablecommunications link, such as a SCSI or Fiber Channel link.

As shown, each media agent 144 may maintain an associated media agentdatabase 152. The media agent database 152 may be stored in a disk orother storage device (not shown) that is local to the secondary storagecomputing device 106 on which the media agent 144 resides. In othercases, the media agent database 152 is stored remotely from thesecondary storage computing device 106.

The media agent database 152 can include, among other things, an index153 including data generated during secondary copy operations and otherstorage or information management operations. The index 153 provides amedia agent 144 or other component with a fast and efficient mechanismfor locating secondary copies 116 or other data stored in the secondarystorage devices 108. In one configuration, a storage manager index 150or other data structure may store data associating a client computingdevice 102 with a particular media agent 144 and/or secondary storagedevice 108, as specified in a storage policy. A media agent index 153 orother data structure associated with the particular media agent 144 mayin turn include information about the stored data.

For instance, for each secondary copy 116, the index 153 may includemetadata such as a list of the data objects (e.g., files/subdirectories,database objects, mailbox objects, etc.), a path to the secondary copy116 on the corresponding secondary storage device 108, locationinformation indicating where the data objects are stored in thesecondary storage device 108, when the data objects were created ormodified, etc. Thus, the index 153 includes metadata associated with thesecondary copies 116 that is readily available for use in storageoperations and other activities without having to be first retrievedfrom the secondary storage device 108. In yet further embodiments, someor all of the data in the index 153 may instead or additionally bestored along with the data in a secondary storage device 108, e.g., witha copy of the index 153.

Because the index 153 maintained in the database 152 may operate as acache, it can also be referred to as an index cache. In such cases,information stored in the index cache 153 typically comprises data thatreflects certain particulars about storage operations that have occurredrelatively recently. After some triggering event, such as after acertain period of time elapses, or the index cache 153 reaches aparticular size, the index cache 153 may be copied or migrated to asecondary storage device(s) 108. This information may need to beretrieved and uploaded back into the index cache 153 or otherwiserestored to a media agent 144 to facilitate retrieval of data from thesecondary storage device(s) 108. In some embodiments, the cachedinformation may include format or containerization information relatedto archives or other files stored on the storage device(s) 108. In thismanner, the index cache 153 allows for accelerated restores.

In some alternative embodiments the media agent 144 generally acts as acoordinator or facilitator of storage operations between clientcomputing devices 102 and corresponding secondary storage devices 108,but does not actually write the data to the secondary storage device108. For instance, the storage manager 140 (or the media agent 144) mayinstruct a client computing device 102 and secondary storage device 108to communicate with one another directly. In such a case the clientcomputing device 102 transmits the data directly to the secondarystorage device 108 according to the received instructions, and viceversa. In some such cases, the media agent 144 may still receive,process, and/or maintain metadata related to the storage operations.Moreover, in these embodiments, the payload data can flow through themedia agent 144 for the purposes of populating the index cache 153maintained in the media agent database 152, but not for writing to thesecondary storage device 108.

The media agent 144 and/or other components such as the storage manager140 may in some cases incorporate additional functionality, such as dataclassification, content indexing, deduplication, encryption,compression, and the like. Further details regarding these and otherfunctions are described below.

Distributed, Scalable Architecture

As described, certain functions of the information management system 100can be distributed amongst various physical and/or logical components inthe system. For instance, one or more of the storage manager 140, dataagents 142, and media agents 144 may reside on computing devices thatare physically separate from one another. This architecture can providea number of benefits.

For instance, hardware and software design choices for each distributedcomponent can be targeted to suit its particular function. The secondarycomputing devices 106 on which the media agents 144 reside can betailored for interaction with associated secondary storage devices 108and provide fast index cache operation, among other specific tasks.Similarly, the client computing device(s) 102 can be selected toeffectively service the applications 110 residing thereon, in order toefficiently produce and store primary data 112.

Moreover, in some cases, one or more of the individual components in theinformation management system 100 can be distributed to multiple,separate computing devices. As one example, for large file systems wherethe amount of data stored in the storage management database 146 isrelatively large, the management database 146 may be migrated to orotherwise reside on a specialized database server (e.g., an SQL server)separate from a server that implements the other functions of thestorage manager 140. This configuration can provide added protectionbecause the database 146 can be protected with standard databaseutilities (e.g., SQL log shipping or database replication) independentfrom other functions of the storage manager 140. The database 146 can beefficiently replicated to a remote site for use in the event of adisaster or other data loss incident at the primary site. Or thedatabase 146 can be replicated to another computing device within thesame site, such as to a higher performance machine in the event that astorage manager host device can no longer service the needs of a growinginformation management system 100.

The distributed architecture also provides both scalability andefficient component utilization. FIG. 1D shows an embodiment of theinformation management system 100 including a plurality of clientcomputing devices 102 and associated data agents 142 as well as aplurality of secondary storage computing devices 106 and associatedmedia agents 144.

Additional components can be added or subtracted based on the evolvingneeds of the information management system 100. For instance, dependingon where bottlenecks are identified, administrators can add additionalclient computing devices 102, secondary storage devices 106 (andcorresponding media agents 144), and/or secondary storage devices 108.

Moreover, each client computing device 102 in some embodiments cancommunicate with any of the media agents 144, e.g., as directed by thestorage manager 140. And each media agent 144 may be able to communicatewith any of the secondary storage devices 108, e.g., as directed by thestorage manager 140. Thus, operations can be routed to the secondarystorage devices 108 in a dynamic and highly flexible manner. Furtherexamples of scalable systems capable of dynamic storage operations areprovided in U.S. Pat. No. 7,246,207, which is incorporated by referenceherein.

In alternative configurations, certain components are not distributedand may instead reside and execute on the same computing device. Forexample, in some embodiments one or more data agents 142 and the storagemanager 140 reside on the same client computing device 102. In anotherembodiment, one or more data agents 142 and one or more media agents 144reside on a single computing device.

Exemplary Types of Information Management Operations

In order to protect and leverage stored data, the information managementsystem 100 can be configured to perform a variety of informationmanagement operations. As will be described, these operations cangenerally include secondary copy and other data movement operations,processing and data manipulation operations, and management operations.

Data Movement Operations

Data movement operations according to certain embodiments are generallyoperations that involve the copying or migration of data (e.g., payloaddata) between different locations in the information management system100. For example, data movement operations can include operations inwhich stored data is copied, migrated, or otherwise transferred fromprimary storage device(s) 104 to secondary storage device(s) 108, fromsecondary storage device(s) 108 to different secondary storage device(s)108, or from primary storage device(s) 104 to different primary storagedevice(s) 104.

Data movement operations can include by way of example, backupoperations, archive operations, information lifecycle managementoperations such as hierarchical storage management operations,replication operations (e.g., continuous data replication operations),snapshot operations, deduplication operations, single-instancingoperations, auxiliary copy operations, and the like. As will bediscussed, some of these operations involve the copying, migration orother movement of data, without actually creating multiple, distinctcopies. Nonetheless, some or all of these operations are referred to as“copy” operations for simplicity.

Backup Operations

A backup operation creates a copy of primary data 112 at a particularpoint in time. Each subsequent backup copy may be maintainedindependently of the first. Further, a backup copy in some embodimentsis stored in a backup format. This can be in contrast to the version inprimary data 112 from which the backup copy is derived, and which mayinstead be stored in a native format of the source application(s) 110.In various cases, backup copies can be stored in a format in which thedata is compressed, encrypted, deduplicated, and/or otherwise modifiedfrom the original application format. For example, a backup copy may bestored in a backup format that facilitates compression and/or efficientlong-term storage.

Backup copies can have relatively long retention periods as compared toprimary data 112, and may be stored on media with slower retrieval timesthan primary data 112 and certain other types of secondary copies 116.On the other hand, backups may have relatively shorter retention periodsthan some other types of secondary copies 116, such as archive copies(described below). Backups may sometimes be stored at on offsitelocation.

Backup operations can include full, synthetic or incremental backups. Afull backup in some embodiments is generally a complete image of thedata to be protected. However, because full backup copies can consume arelatively large amount of storage, it can be useful to use a fullbackup copy as a baseline and only store changes relative to the fullbackup copy for subsequent backup copies.

For instance, a differential backup operation (or cumulative incrementalbackup operation) tracks and stores changes that have occurred since thelast full backup. Differential backups can grow quickly in size, but canprovide relatively efficient restore times because a restore can becompleted in some cases using only the full backup copy and the latestdifferential copy.

An incremental backup operation generally tracks and stores changessince the most recent backup copy of any type, which can greatly reducestorage utilization. In some cases, however, restore times can berelatively long in comparison to full or differential backups becausecompleting a restore operation may involve accessing a full backup inaddition to multiple incremental backups.

Any of the above types of backup operations can be at the file-level,e.g., where the information management system 100 generally trackschanges to files at the file-level, and includes copies of files in thebackup copy. In other cases, block-level backups are employed, wherefiles are broken into constituent blocks, and changes are tracked at theblock-level. Upon restore, the information management system 100reassembles the blocks into files in a transparent fashion.

Far less data may actually be transferred and copied to the secondarystorage devices 108 during a block-level copy than during a file-levelcopy, resulting in faster execution times. However, when restoring ablock-level copy, the process of locating constituent blocks cansometimes result in longer restore times as compared to file-levelbackups. Similar to backup operations, the other types of secondary copyoperations described herein can also be implemented at either thefile-level or the block-level.

Archive Operations

Because backup operations generally involve maintaining a version of thecopied data in primary data 112 and also maintaining backup copies insecondary storage device(s) 108, they can consume significant storagecapacity. To help reduce storage consumption, an archive operationaccording to certain embodiments creates a secondary copy 116 by bothcopying and removing source data. Or, seen another way, archiveoperations can involve moving some or all of the source data to thearchive destination. Thus, data satisfying criteria for removal (e.g.,data of a threshold age or size) from the source copy may be removedfrom source storage. Archive copies are sometimes stored in an archiveformat or other non-native application format. The source data may beprimary data 112 or a secondary copy 116, depending on the situation. Aswith backup copies, archive copies can be stored in a format in whichthe data is compressed, encrypted, deduplicated, and/or otherwisemodified from the original application format.

In addition, archive copies may be retained for relatively long periodsof time (e.g., years) and, in some cases, are never deleted. Archivecopies are generally retained for longer periods of time than backupcopies, for example. In certain embodiments, archive copies may be madeand kept for extended periods in order to meet compliance regulations.

Moreover, when primary data 112 is archived, in some cases the archivedprimary data 112 or a portion thereof is deleted when creating thearchive copy. Thus, archiving can serve the purpose of freeing up spacein the primary storage device(s) 104. Similarly, when a secondary copy116 is archived, the secondary copy 116 may be deleted, and an archivecopy can therefore serve the purpose of freeing up space in secondarystorage device(s) 108. In contrast, source copies often remain intactwhen creating backup copies.

Snapshot Operations

Snapshot operations can provide a relatively lightweight, efficientmechanism for protecting data. From an end-user viewpoint, a snapshotmay be thought of as an “instant” image of the primary data 112 at agiven point in time. In one embodiment, a snapshot may generally capturethe directory structure of an object in primary data 112 such as a fileor volume or other data set at a particular moment in time and may alsopreserve file attributes and contents. A snapshot in some cases iscreated relatively quickly, e.g., substantially instantly, using aminimum amount of file space, but may still function as a conventionalfile system backup.

A snapshot copy in many cases can be made quickly and withoutsignificantly impacting primary computing resources because largeamounts of data need not be copied or moved. In some embodiments, asnapshot may exist as a virtual file system, parallel to the actual filesystem. Users in some cases gain read-only access to the record of filesand directories of the snapshot. By electing to restore primary data 112from a snapshot taken at a given point in time, users may also returnthe current file system to the state of the file system that existedwhen the snapshot was taken.

Some types of snapshots do not actually create another physical copy ofall the data as it existed at the particular point in time, but maysimply create pointers that are able to map files and directories tospecific memory locations (e.g., disk blocks) where the data resides, asit existed at the particular point in time. For example, a snapshot copymay include a set of pointers derived from the file system or anapplication. Each pointer points to a respective stored data block, socollectively, the set of pointers reflect the storage location and stateof the data object (e.g., file(s) or volume(s) or data set(s)) at aparticular point in time when the snapshot copy was created.

In some embodiments, once a snapshot has been taken, subsequent changesto the file system typically do not overwrite the blocks in use at thetime of the snapshot. Therefore, the initial snapshot may use only asmall amount of disk space needed to record a mapping or other datastructure representing or otherwise tracking the blocks that correspondto the current state of the file system. Additional disk space isusually required only when files and directories are actually modifiedlater. Furthermore, when files are modified, typically only the pointerswhich map to blocks are copied, not the blocks themselves. In someembodiments, for example in the case of “copy-on-write” snapshots, whena block changes in primary storage, the block is copied to secondarystorage or cached in primary storage before the block is overwritten inprimary storage. The snapshot mapping of file system data is alsoupdated to reflect the changed block(s) at that particular point intime. In some other cases, a snapshot includes a full physical copy ofall or substantially all of the data represented by the snapshot.Further examples of snapshot operations are provided in U.S. Pat. No.7,529,782, which is incorporated by reference herein.

Replication Operations

Another type of secondary copy operation is a replication operation.Some types of secondary copies 116 are used to periodically captureimages of primary data 112 at particular points in time (e.g., backups,archives, and snapshots). However, it can also be useful for recoverypurposes to protect primary data 112 in a more continuous fashion, byreplicating the primary data 112 substantially as changes occur. In somecases a replication copy can be a mirror copy, for instance, wherechanges made to primary data 112 are mirrored to another location (e.g.,to secondary storage device(s) 108). By copying each write operation tothe replication copy, two storage systems are kept synchronized orsubstantially synchronized so that they are virtually identical atapproximately the same time. Where entire disk volumes are mirrored,however, mirroring can require significant amount of storage space andutilizes a large amount of processing resources.

According to some embodiments storage operations are performed onreplicated data that represents a recoverable state, or “known goodstate” of a particular application running on the source system. Forinstance, in certain embodiments, known good replication copies may beviewed as copies of primary data 112. This feature allows the system todirectly access, copy, restore, backup or otherwise manipulate thereplication copies as if the data was the “live”, primary data 112. Thiscan reduce access time, storage utilization, and impact on sourceapplications 110, among other benefits.

Based on known good state information, the information management system100 can replicate sections of application data that represent arecoverable state rather than rote copying of blocks of data. Examplesof compatible replication operations (e.g., continuous data replication)are provided in U.S. Pat. No. 7,617,262, which is incorporated byreference herein.

Deduplication/Single-Instancing Operations

Another type of data movement operation is deduplication, which isuseful to reduce the amount of data within the system. For instance,some or all of the above-described secondary storage operations caninvolve deduplication in some fashion. New data is read, broken downinto blocks (e.g., sub-file level blocks) of a selected granularity,compared with blocks that are already stored, and only the new blocksare stored. Blocks that already exist are represented as pointers to thealready stored data.

In order to stream-line the comparison process, the informationmanagement system 100 may calculate and/or store signatures (e.g.,hashes) corresponding to the individual data blocks and compare thehashes instead of comparing entire data blocks. In some cases, only asingle instance of each element is stored, and deduplication operationsmay therefore be referred to interchangeably as “single-instancing”operations. Depending on the implementation, however, deduplication orsingle-instancing operations can store more than one instance of certaindata blocks, but nonetheless significantly reduce data redundancy.Moreover, single-instancing in some cases is distinguished fromdeduplication as a process of analyzing and reducing data at the filelevel, rather than the sub-file level.

Depending on the embodiment, deduplication blocks can be of fixed orvariable length. Using variable length blocks can provide enhanceddeduplication by responding to changes in the data stream, but caninvolve complex processing. In some cases, the information managementsystem 100 utilizes a technique for dynamically aligning deduplicationblocks (e.g., fixed-length blocks) based on changing content in the datastream, as described in U.S. Pat. Pub. No. 2012/0084269, which isincorporated by reference herein.

The information management system 100 can perform deduplication in avariety of manners at a variety of locations in the informationmanagement system 100. For instance, in some embodiments, theinformation management system 100 implements “target-side” deduplicationby deduplicating data (e.g., secondary copies 116) stored in thesecondary storage devices 108. In some such cases, the media agents 144are generally configured to manage the deduplication process. Forinstance, one or more of the media agents 144 maintain a correspondingdeduplication database that stores deduplication information (e.g.,datablock signatures). Examples of such a configuration are provided inU.S. Pat. Pub. No. 2012/0150826, which is incorporated by referenceherein. Deduplication can also be performed on the “source-side” (or“client-side”), e.g., to reduce the amount of traffic between the mediaagents 144 and the client computing device(s) 102 and/or reduceredundant data stored in the primary storage devices 104. Examples ofsuch deduplication techniques are provided in U.S. Pat. Pub. No.2012/0150818, which is incorporated by reference herein.

Information Lifecycle Management and Hierarchical Storage ManagementOperations

In some embodiments, files and other data over their lifetime move frommore expensive, quick access storage to less expensive, slower accessstorage. Operations associated with moving data through various tiers ofstorage are sometimes referred to as information lifecycle management(ILM) operations.

One type of ILM operation is a hierarchical storage management (HSM)operation. A HSM operation is generally an operation for automaticallymoving data between classes of storage devices, such as betweenhigh-cost and low-cost storage devices. For instance, an HSM operationmay involve movement of data from primary storage devices 104 tosecondary storage devices 108, or between tiers of secondary storagedevices 108. With each tier, the storage devices may be progressivelyrelatively cheaper, have relatively slower access/restore times, etc.For example, movement of data between tiers may occur as data becomesless important over time.

In some embodiments, an HSM operation is similar to an archive operationin that creating an HSM copy may (though not always) involve deletingsome of the source data. For example, an HSM copy may include data fromprimary data 112 or a secondary copy 116 that is larger than a givensize threshold or older than a given age threshold and that is stored ina backup format.

Often, and unlike some types of archive copies, HSM data that is removedor aged from the source copy is replaced by a logical reference pointeror stub. The reference pointer or stub can be stored in the primarystorage device 104 to replace the deleted data in primary data 112 (orother source copy) and to point to or otherwise indicate the newlocation in a secondary storage device 108.

According to one example, files are generally moved between higher andlower cost storage depending on how often the files are accessed. When auser requests access to the HSM data that has been removed or migrated,the information management system 100 uses the stub to locate the dataand often make recovery of the data appear transparent, even though theHSM data may be stored at a location different from the remaining sourcedata. The stub may also include some metadata associated with thecorresponding data, so that a file system and/or application can providesome information about the data object and/or a limited-functionalityversion (e.g., a preview) of the data object.

An HSM copy may be stored in a format other than the native applicationformat (e.g., where the data is compressed, encrypted, deduplicated,and/or otherwise modified from the original application format). In somecases, copies which involve the removal of data from source storage andthe maintenance of stub or other logical reference information on sourcestorage may be referred to generally as “on-line archive copies”. On theother hand, copies which involve the removal of data from source storagewithout the maintenance of stub or other logical reference informationon source storage may be referred to as “off-line archive copies”.

Auxiliary Copy and Disaster Recovery Operations

An auxiliary copy is generally a copy operation in which a copy iscreated of an existing secondary copy 116. For instance, an initial or“primary” secondary copy 116 may be generated using or otherwise bederived from primary data 112, whereas an auxiliary copy is generatedfrom the initial secondary copy 116. Auxiliary copies can be used tocreate additional standby copies of data and may reside on differentsecondary storage devices 108 than initial secondary copies 116. Thus,auxiliary copies can be used for recovery purposes if initial secondarycopies 116 become unavailable. Exemplary compatible auxiliary copytechniques are described in further detail in U.S. Pat. No. 8,230,195,which is incorporated by reference herein.

The information management system 100 may also perform disaster recoveryoperations that make or retain disaster recovery copies, often assecondary, high-availability disk copies. The information managementsystem 100 may create secondary disk copies and store the copies atdisaster recovery locations using auxiliary copy or replicationoperations, such as continuous data replication technologies. Dependingon the particular data protection goals, disaster recovery locations canbe remote from the client computing devices 102 and primary storagedevices 104, remote from some or all of the secondary storage devices108, or both.

Data Processing and Manipulation Operations

As indicated, the information management system 100 can also beconfigured to implement certain data manipulation operations, whichaccording to certain embodiments are generally operations involving theprocessing or modification of stored data. Some data manipulationoperations include content indexing operations and classificationoperations can be useful in leveraging the data under management toprovide enhanced search and other features. Other data manipulationoperations such as compression and encryption can provide data reductionand security benefits, respectively.

Data manipulation operations can be different than data movementoperations in that they do not necessarily involve the copying,migration or other transfer of data (e.g., primary data 112 or secondarycopies 116) between different locations in the system. For instance,data manipulation operations may involve processing (e.g., offlineprocessing) or modification of already stored primary data 112 and/orsecondary copies 116. However, in some embodiments data manipulationoperations are performed in conjunction with data movement operations.As one example, the information management system 100 may encrypt datawhile performing an archive operation.

Content Indexing

In some embodiments, the information management system 100 “contentindexes” data stored within the primary data 112 and/or secondary copies116, providing enhanced search capabilities for data discovery and otherpurposes. The content indexing can be used to identify files or otherdata objects having pre-defined content (e.g., user-defined keywords orphrases), metadata (e.g., email metadata such as “to”, “from”, “cc”,“bcc”, attachment name, received time, etc.).

The information management system 100 generally organizes and cataloguesthe results in a content index, which may be stored within the mediaagent database 152, for example. The content index can also include thestorage locations of (or pointer references to) the indexed data in theprimary data 112 or secondary copies 116, as appropriate. The resultsmay also be stored, in the form of a content index database orotherwise, elsewhere in the information management system 100 (e.g., inthe primary storage devices 104, or in the secondary storage device108). Such index data provides the storage manager 140 or anothercomponent with an efficient mechanism for locating primary data 112and/or secondary copies 116 of data objects that match particularcriteria.

For instance, search criteria can be specified by a user through userinterface 158 of the storage manager 140. In some cases, the informationmanagement system 100 analyzes data and/or metadata in secondary copies116 to create an “off-line” content index, without significantlyimpacting the performance of the client computing devices 102. Dependingon the embodiment, the system can also implement “on-line” contentindexing, e.g., of primary data 112. Examples of compatible contentindexing techniques are provided in U.S. Pat. No. 8,170,995, which isincorporated by reference herein.

Classification Operations—Metabase

In order to help leverage the data stored in the information managementsystem 100, one or more components can be configured to scan data and/orassociated metadata for classification purposes to populate a metabaseof information. Such scanned, classified data and/or metadata may beincluded in a separate database and/or on a separate storage device fromprimary data 112 (and/or secondary copies 116), such that metabaserelated operations do not significantly impact performance on othercomponents in the information management system 100.

In other cases, the metabase(s) may be stored along with primary data112 and/or secondary copies 116. Files or other data objects can beassociated with user-specified identifiers (e.g., tag entries) in themedia agent 144 (or other indices) to facilitate searches of stored dataobjects. Among a number of other benefits, the metabase can also allowefficient, automatic identification of files or other data objects toassociate with secondary copy or other information management operations(e.g., in lieu of scanning an entire file system). Examples ofcompatible metabases and data classification operations are provided inU.S. Pat. Nos. 8,229,954 and 7,747,579, which are incorporated byreference herein.

Encryption Operations

The information management system 100 in some cases is configured toprocess data (e.g., files or other data objects, secondary copies 116,etc.), according to an appropriate encryption algorithm (e.g., Blowfish,Advanced Encryption Standard [AES], Triple Data Encryption Standard[3-DES], etc.) to limit access and provide data security in theinformation management system 100.

The information management system 100 in some cases encrypts the data atthe client level, such that the client computing devices 102 (e.g., thedata agents 142) encrypt the data prior to forwarding the data to othercomponents, e.g., before sending the data media agents 144 during asecondary copy operation. In such cases, the client computing device 102may maintain or have access to an encryption key or passphrase fordecrypting the data upon restore. Encryption can also occur whencreating copies of secondary copies, e.g., when creating auxiliarycopies. In yet further embodiments, the secondary storage devices 108can implement built-in, high performance hardware encryption.

Management Operations

Certain embodiments leverage the integrated, ubiquitous nature of theinformation management system 100 to provide useful system-widemanagement functions. As two non-limiting examples, the informationmanagement system 100 can be configured to implement operationsmanagement and e-discovery functions.

Operations management can generally include monitoring and managing thehealth and performance of information management system 100 by, withoutlimitation, performing error tracking, generating granularstorage/performance metrics (e.g., job success/failure information,deduplication efficiency, etc.), generating storage modeling and costinginformation, and the like.

Such information can be provided to users via the user interface 158 ina single, integrated view. For instance, the integrated user interface158 can include an option to show a “virtual view” of the system thatgraphically depicts the various components in the system usingappropriate icons. The operations management functionality canfacilitate planning and decision-making. For example, in someembodiments, a user may view the status of some or all jobs as well asthe status of each component of the information management system 100.Users may then plan and make decisions based on this data. For instance,a user may view high-level information regarding storage operations forthe information management system 100, such as job status, componentstatus, resource status (e.g., network pathways, etc.), and otherinformation. The user may also drill down or use other means to obtainmore detailed information regarding a particular component, job, or thelike.

In some cases the information management system 100 alerts a user suchas a system administrator when a particular resource is unavailable orcongested. For example, a particular primary storage device 104 orsecondary storage device 108 might be full or require additionalcapacity. Or a component may be unavailable due to hardware failure,software problems, or other reasons. In response, the informationmanagement system 100 may suggest solutions to such problems when theyoccur (or provide a warning prior to occurrence). For example, thestorage manager 140 may alert the user that a secondary storage device108 is full or otherwise congested. The storage manager 140 may thensuggest, based on job and data storage information contained in itsdatabase 146, an alternate secondary storage device 108.

Other types of corrective actions may include suggesting an alternatedata path to a particular primary or secondary storage device 104, 108,or dividing data to be stored among various available primary orsecondary storage devices 104, 108 as a load balancing measure or tootherwise optimize storage or retrieval time. Such suggestions orcorrective actions may be performed automatically, if desired. Furtherexamples of some compatible operations management techniques and ofinterfaces providing an integrated view of an information managementsystem are provided in U.S. Pat. No. 7,343,453, which is incorporated byreference herein. In some embodiments, the storage manager 140implements the operations management functions described herein.

The information management system 100 can also be configured to performsystem-wide e-discovery operations in some embodiments. In general,e-discovery operations provide a unified collection and searchcapability for data in the system, such as data stored in the secondarystorage devices 108 (e.g., backups, archives, or other secondary copies116). For example, the information management system 100 may constructand maintain a virtual repository for data stored in the informationmanagement system 100 that is integrated across source applications 110,different storage device types, etc. According to some embodiments,e-discovery utilizes other techniques described herein, such as dataclassification and/or content indexing.

Information Management Policies

As indicated previously, an information management policy 148 caninclude a data structure or other information source that specifies aset of parameters (e.g., criteria and rules) associated with secondarycopy or other information management operations.

One type of information management policy 148 is a storage policy.According to certain embodiments, a storage policy generally comprises alogical container that defines (or includes information sufficient todetermine) one or more of the following items: (1) what data will beassociated with the storage policy; (2) a destination to which the datawill be stored; (3) datapath information specifying how the data will becommunicated to the destination; (4) the type of storage operation to beperformed; and (5) retention information specifying how long the datawill be retained at the destination.

Data associated with a storage policy can be logically organized intogroups, which can be referred to as “sub-clients”. A sub-client mayrepresent static or dynamic associations of portions of a data volume.Sub-clients may represent mutually exclusive portions. Thus, in certainembodiments, a portion of data may be given a label and the associationis stored as a static entity in an index, database or other storagelocation.

Sub-clients may also be used as an effective administrative scheme oforganizing data according to data type, department within theenterprise, storage preferences, or the like. Depending on theconfiguration, sub-clients can correspond to files, folders, virtualmachines, databases, etc. In one exemplary scenario, an administratormay find it preferable to separate e-mail data from financial data usingtwo different sub-clients.

A storage policy can define where data is stored by specifying a targetor destination storage device (or group of storage devices). Forinstance, where the secondary storage device 108 includes a group ofdisk libraries, the storage policy may specify a particular disk libraryfor storing the sub-clients associated with the policy. As anotherexample, where the secondary storage devices 108 include one or moretape libraries, the storage policy may specify a particular tape libraryfor storing the sub-clients associated with the storage policy, and mayalso specify a drive pool and a tape pool defining a group of tapedrives and a group of tapes, respectively, for use in storing thesub-client data.

Datapath information can also be included in the storage policy. Forinstance, the storage policy may specify network pathways and componentsto utilize when moving the data to the destination storage device(s). Insome embodiments, the storage policy specifies one or more media agents144 for conveying data (e.g., one or more sub-clients) associated withthe storage policy between the source (e.g., one or more host clientcomputing devices 102) and destination (e.g., a particular targetsecondary storage device 108).

A storage policy can also specify the type(s) of operations associatedwith the storage policy, such as a backup, archive, snapshot, auxiliarycopy, or the like. Retention information can specify how long the datawill be kept, depending on organizational needs (e.g., a number of days,months, years, etc.)

The information management policies 148 may also include one or morescheduling policies specifying when and how often to perform operations.Scheduling information may specify with what frequency (e.g., hourly,weekly, daily, event-based, etc.) or under what triggering conditionssecondary copy or other information management operations will takeplace. Scheduling policies in some cases are associated with particularcomponents, such as particular sub-clients, client computing device 102,and the like. In one configuration, a separate scheduling policy ismaintained for particular sub-clients on a client computing device 102.The scheduling policy specifies that those sub-clients are to be movedto secondary storage devices 108 every hour according to storagepolicies associated with the respective sub-clients.

When adding a new client computing device 102, administrators canmanually configure information management policies 148 and/or othersettings, e.g., via the user interface 158. However, this can be aninvolved process resulting in delays, and it may be desirable to begindata protecting operations quickly.

Thus, in some embodiments, the information management system 100automatically applies a default configuration to client computing device102. As one example, when a data agent(s) 142 is installed on a clientcomputing devices 102, the installation script may register the clientcomputing device 102 with the storage manager 140, which in turn appliesthe default configuration to the new client computing device 102. Inthis manner, data protection operations can begin substantiallyimmediately. The default configuration can include a default storagepolicy, for example, and can specify any appropriate informationsufficient to begin data protection operations. This can include a typeof data protection operation, scheduling information, a target secondarystorage device 108, data path information (e.g., a particular mediaagent 144), and the like.

Other types of information management policies 148 are possible. Forinstance, the information management policies 148 can also include oneor more audit or security policies. An audit policy is a set ofpreferences, rules and/or criteria that protect sensitive data in theinformation management system 100. For example, an audit policy maydefine “sensitive objects” as files or objects that contain particularkeywords (e.g. “confidential,” or “privileged”) and/or are associatedwith particular keywords (e.g., in metadata) or particular flags (e.g.,in metadata identifying a document or email as personal, confidential,etc.).

An audit policy may further specify rules for handling sensitiveobjects. As an example, an audit policy may require that a reviewerapprove the transfer of any sensitive objects to a cloud storage site,and that if approval is denied for a particular sensitive object, thesensitive object should be transferred to a local storage device 104instead. To facilitate this approval, the audit policy may furtherspecify how a secondary storage computing device 106 or other systemcomponent should notify a reviewer that a sensitive object is slated fortransfer.

In some implementations, the information management policies 148 mayinclude one or more provisioning policies. A provisioning policy caninclude a set of preferences, priorities, rules, and/or criteria thatspecify how clients 102 (or groups thereof) may utilize systemresources, such as available storage on cloud storage and/or networkbandwidth. A provisioning policy specifies, for example, data quotas forparticular client computing devices 102 (e.g. a number of gigabytes thatcan be stored monthly, quarterly or annually). The storage manager 140or other components may enforce the provisioning policy. For instance,the media agents 144 may enforce the policy when transferring data tosecondary storage devices 108. If a client computing device 102 exceedsa quota, a budget for the client computing device 102 (or associateddepartment) is adjusted accordingly or an alert may trigger.

While the above types of information management policies 148 have beendescribed as separate policies, one or more of these can be generallycombined into a single information management policy 148. For instance,a storage policy may also include or otherwise be associated with one ormore scheduling, audit, or provisioning policies. Moreover, whilestorage policies are typically associated with moving and storing data,other policies may be associated with other types of informationmanagement operations. The following is a non-exhaustive list of itemsthe information management policies 148 may specify:

-   -   schedules or other timing information, e.g., specifying when        and/or how often to perform information management operations;    -   the type of secondary copy 116 and/or secondary copy format        (e.g., snapshot, backup, archive, HSM, etc.);    -   a location or a class or quality of storage for storing        secondary copies 116 (e.g., one or more particular secondary        storage devices 108);    -   preferences regarding whether and how to encrypt, compress,        deduplicate, or otherwise modify or transform secondary copies        116;    -   which system components and/or network pathways (e.g., preferred        media agents 144) should be used to perform secondary storage        operations;    -   resource allocation between different computing devices or other        system components used in performing information management        operations (e.g., bandwidth allocation, available storage        capacity, etc.);    -   whether and how to synchronize or otherwise distribute files or        other data objects across multiple computing devices or hosted        services; and    -   retention information specifying the length of time primary data        112 and/or secondary copies 116 should be retained, e.g., in a        particular class or tier of storage devices, or within the        information management system 100.

Policies can additionally specify or depend on a variety of historicalor current criteria that may be used to determine which rules to applyto a particular data object, system component, or information managementoperation, such as:

-   -   frequency with which primary data 112 or a secondary copy 116 of        a data object or metadata has been or is predicted to be used,        accessed, or modified;    -   time-related factors (e.g., aging information such as time since        the creation or modification of a data object);    -   deduplication information (e.g., hashes, data blocks,        deduplication block size, deduplication efficiency or other        metrics);    -   an estimated or historic usage or cost associated with different        components (e.g., with secondary storage devices 108);    -   the identity of users, applications 110, client computing        devices 102 and/or other computing devices that created,        accessed, modified, or otherwise utilized primary data 112 or        secondary copies 116;    -   a relative sensitivity (e.g., confidentiality) of a data object,        e.g., as determined by its content and/or metadata;    -   the current or historical storage capacity of various storage        devices;    -   the current or historical network capacity of network pathways        connecting various components within the storage operation cell;    -   access control lists or other security information; and    -   the content of a particular data object (e.g., its textual        content) or of metadata associated with the data object.        Exemplary Storage Policy and Secondary Storage Operations

FIG. 1E shows a data flow data diagram depicting performance of storageoperations by an embodiment of an information management system 100,according to an exemplary data storage policy 148A. The informationmanagement system 100 includes a storage manger 140, a client computingdevice 102 having a file system data agent 142A and an email data agent142B residing thereon, a primary storage device 104, two media agents144A, 144B, and two secondary storage devices 108A, 108B: a disk library108A and a tape library 108B. As shown, the primary storage device 104includes primary data 112A, 112B associated with a file systemsub-client and an email sub-client, respectively.

As indicated by the dashed box, the second media agent 144B and the tapelibrary 108B are “off-site”, and may therefore be remotely located fromthe other components in the information management system 100 (e.g., ina different city, office building, etc.). In this manner, informationstored on the tape library 108B may provide protection in the event of adisaster or other failure.

The file system sub-client and its associated primary data 112A incertain embodiments generally comprise information generated by the filesystem and/or operating system of the client computing device 102, andcan include, for example, file system data (e.g., regular files, filetables, mount points, etc.), operating system data (e.g., registries,event logs, etc.), and the like. The e-mail sub-client, on the otherhand, and its associated primary data 112B, include data generated by ane-mail client application operating on the client computing device 102,and can include mailbox information, folder information, emails,attachments, associated database information, and the like. As describedabove, the sub-clients can be logical containers, and the data includedin the corresponding primary data 112A, 112B may or may not be storedcontiguously.

The exemplary storage policy 148A includes a backup copy rule set 160, adisaster recovery copy rule set 162, and a compliance copy rule set 164.The backup copy rule set 160 specifies that it is associated with a filesystem sub-client 166 and an email sub-client 168. Each of thesesub-clients 166, 168 are associated with the particular client computingdevice 102. The backup copy rule set 160 further specifies that thebackup operation will be written to the disk library 108A, anddesignates a particular media agent 144A to convey the data to the disklibrary 108A. Finally, the backup copy rule set 160 specifies thatbackup copies created according to the rule set 160 are scheduled to begenerated on an hourly basis and to be retained for 30 days. In someother embodiments, scheduling information is not included in the storagepolicy 148A, and is instead specified by a separate scheduling policy.

The disaster recovery copy rule set 162 is associated with the same twosub-clients 166, 168. However, the disaster recovery copy rule set 162is associated with the tape library 108B, unlike the backup copy ruleset 160. Moreover, the disaster recovery copy rule set 162 specifiesthat a different media agent 144B than the media agent 144A associatedwith the backup copy rule set 160 will be used to convey the data to thetape library 108B. As indicated, disaster recovery copies createdaccording to the rule set 162 will be retained for 60 days, and will begenerated on a daily basis. Disaster recovery copies generated accordingto the disaster recovery copy rule set 162 can provide protection in theevent of a disaster or other data-loss event that would affect thebackup copy 116A maintained on the disk library 108A.

The compliance copy rule set 164 is only associated with the emailsub-client 166, and not the file system sub-client 168. Compliancecopies generated according to the compliance copy rule set 164 willtherefore not include primary data 112A from the file system sub-client166. For instance, the organization may be under an obligation to storemaintain copies of email data for a particular period of time (e.g., 10years) to comply with state or federal regulations, while similarregulations do not apply to the file system data. The compliance copyrule set 164 is associated with the same tape library 108B and mediaagent 144B as the disaster recovery copy rule set 162, although adifferent storage device or media agent could be used in otherembodiments. Finally, the compliance copy rule set 164 specifies thatcopies generated under the compliance copy rule set 164 will be retainedfor 10 years, and will be generated on a quarterly basis.

At step 1, the storage manager 140 initiates a backup operationaccording to the backup copy rule set 160. For instance, a schedulingservice running on the storage manager 140 accesses schedulinginformation from the backup copy rule set 160 or a separate schedulingpolicy associated with the client computing device 102, and initiates abackup copy operation on an hourly basis. Thus, at the scheduled timeslot the storage manager 140 sends instructions to the client computingdevice 102 to begin the backup operation.

At step 2, the file system data agent 142A and the email data agent 142Bresiding on the client computing device 102 respond to the instructionsreceived from the storage manager 140 by accessing and processing theprimary data 112A, 112B involved in the copy operation from the primarystorage device 104. Because the operation is a backup copy operation,the data agent(s) 142A, 142B may format the data into a backup format orotherwise process the data.

At step 3, the client computing device 102 communicates the retrieved,processed data to the first media agent 144A, as directed by the storagemanager 140, according to the backup copy rule set 160. In some otherembodiments, the information management system 100 may implement aload-balancing, availability-based, or other appropriate algorithm toselect from the available set of media agents 144A, 144B. Regardless ofthe manner the media agent 144A is selected, the storage manager 140 mayfurther keep a record in the storage manager database 140 of theassociation between the selected media agent 144A and the clientcomputing device 102 and/or between the selected media agent 144A andthe backup copy 116A.

The target media agent 144A receives the data from the client computingdevice 102, and at step 4 conveys the data to the disk library 108A tocreate the backup copy 116A, again at the direction of the storagemanager 140 and according to the backup copy rule set 160. The secondarystorage device 108A can be selected in other ways. For instance, themedia agent 144A may have a dedicated association with a particularsecondary storage device(s), or the storage manager 140 or media agent144A may select from a plurality of secondary storage devices, e.g.,according to availability, using one of the techniques described in U.S.Pat. No. 7,246,207, which is incorporated by reference herein.

The media agent 144A can also update its index 153 to include dataand/or metadata related to the backup copy 116A, such as informationindicating where the backup copy 116A resides on the disk library 108A,data and metadata for cache retrieval, etc. After the 30 day retentionperiod expires, the storage manager 140 instructs the media agent 144Ato delete the backup copy 116A from the disk library 108A.

At step 5, the storage manager 140 initiates the creation of a disasterrecovery copy 116B according to the disaster recovery copy rule set 162.For instance, at step 6, based on instructions received from the storagemanager 140 at step 5, the specified media agent 144B retrieves the mostrecent backup copy 116A from the disk library 108A.

At step 7, again at the direction of the storage manager 140 and asspecified in the disaster recovery copy rule set 162, the media agent144B uses the retrieved data to create a disaster recovery copy 116B onthe tape library 108B. In some cases, the disaster recovery copy 116B isa direct, mirror copy of the backup copy 116A, and remains in the backupformat. In other embodiments, the disaster recovery copy 116C may begenerated in some other manner, such as by using the primary data 112A,112B from the storage device 104 as source data. The disaster recoverycopy operation is initiated once a day and the disaster recovery copies116A are deleted after 60 days.

At step 8, the storage manager 140 initiates the creation of acompliance copy 116C, according to the compliance copy rule set 164. Forinstance, the storage manager 140 instructs the media agent 144B tocreate the compliance copy 116C on the tape library 108B at step 9, asspecified in the compliance copy rule set 164. In the example, thecompliance copy 116C is generated using the disaster recovery copy 116B.In other embodiments, the compliance copy 116C is instead generatedusing either the primary data 112B corresponding to the email sub-clientor using the backup copy 116A from the disk library 108A as source data.As specified, compliance copies 116C are created quarterly, and aredeleted after ten years.

While not shown in FIG. 1E, at some later point in time, a restoreoperation can be initiated involving one or more of the secondary copies116A, 116B, 116C. As one example, a user may manually initiate a restoreof the backup copy 116A by interacting with the user interface 158 ofthe storage manager 140. The storage manager 140 then accesses data inits index 150 (and/or the respective storage policy 148A) associatedwith the selected backup copy 116A to identify the appropriate mediaagent 144A and/or secondary storage device 116A.

In other cases, a media agent may be selected for use in the restoreoperation based on a load balancing algorithm, an availability basedalgorithm, or other criteria. The selected media agent 144A retrievesthe data from the disk library 108A. For instance, the media agent 144Amay access its index 153 to identify a location of the backup copy 116Aon the disk library 108A, or may access location information residing onthe disk 108A itself.

When the backup copy 116A was recently created or accessed, the mediaagent 144A accesses a cached version of the backup copy 116A residing inthe media agent index 153, without having to access the disk library108A for some or all of the data. Once it has retrieved the backup copy116A, the media agent 144A communicates the data to the source clientcomputing device 102. Upon receipt, the file system data agent 142A andthe email data agent 142B may unpackage (e.g., restore from a backupformat to the native application format) the data in the backup copy116A and restore the unpackaged data to the primary storage device 104.

Exemplary Secondary Copy Formatting

The formatting and structure of secondary copies 116 can vary, dependingon the embodiment. In some cases, secondary copies 116 are formatted asa series of logical data units or “chunks” (e.g., 512 MB, 1 GB, 2 GB, 4GB, or 8 GB chunks). This can facilitate efficient communication andwriting to secondary storage devices 108, e.g., according to resourceavailability. For example, a single secondary copy 116 may be written ona chunk-by-chunk basis to a single secondary storage device 108 oracross multiple secondary storage devices 108. In some cases, users canselect different chunk sizes, e.g., to improve throughput to tapestorage devices.

Generally, each chunk can include a header and a payload. The payloadcan include files (or other data units) or subsets thereof included inthe chunk, whereas the chunk header generally includes metadata relatingto the chunk, some or all of which may be derived from the payload. Forexample, during a secondary copy operation, the media agent 144, storagemanager 140, or other component may divide the associated files intochunks and generate headers for each chunk by processing the constituentfiles.

The headers can include a variety of information such as fileidentifier(s), volume(s), offset(s), or other information associatedwith the payload data items, a chunk sequence number, etc. Importantly,in addition to being stored with the secondary copy 116 on the secondarystorage device 108, the chunk headers can also be stored to the index153 of the associated media agent(s) 144 and/or the storage managerindex 150. This is useful in some cases for providing faster processingof secondary copies 116 during restores or other operations. In somecases, once a chunk is successfully transferred to a secondary storagedevice 108, the secondary storage device 108 returns an indication ofreceipt, e.g., to the media agent 144 and/or storage manager 140, whichmay update their respective indexes 150, 153 accordingly.

During restore, chunks may be processed (e.g., by the media agent 144)according to the information in the chunk header to reassemble thefiles. Additional information relating to chunks can be found in U.S.Pat. No. 8,156,086, which is incorporated by reference herein.

File Level Restore from Block Level Backup

FIG. 2 shows a portion of an example data storage system configured toprovide file level restore capability from a block level secondary copy.The example system includes one or more of the following components: adestination client 285, an information store 290 associated with thedestination client 285, a storage manager 250, a media agent 205, and asecondary storage device 215. Each of these components may be similar toor the same as the corresponding components shown in any of FIGS. 1A-1E,where applicable. For instance, the destination client 285 and mediaagent 205 may correspond to one of the clients 102 and one of the mediaagents 144 of FIG. 1D, respectively. While not shown specifically, themedia agent 205 may be implemented on a secondary storage computingdevice.

The destination client 285 includes a data agent(s) 295 and an operatingsystem 230 residing thereon. A device interface 234 (e.g., a pseudodevice) can be instantiated on the destination client 285 for thepurposes of performing a file level restore, and will be described infurther detail below.

The data agent 295 can be similar or the same as the data agent 142described with respect to FIG. 1, and can be configured to perform orcontribute to creating and recovering/restoring secondary copies of datagenerated by one or more applications (not shown) executing on thedestination client 285. For instance, as described with respect to FIG.1, each data agent 295 may be specific to and handle data generated by aparticular application executing on the client 285. For example, thedata agent may 295 be configured to process data for a particular filesystem residing on the client 295. Compatible file systems include,without limitations, New Technology File System (NTFS)-based filesystems such as Windows (e.g., Windows XP, Windows 7, etc.), FileAllocation Table (FAT)-based file systems, the Unix file system (e.g.,Solaris ZFS, Solaris UFS), and the like, Linux (e.g., ext2, ext3, ext4,resierfs, xfs). In some cases, more than one type of file system may beinstalled on a particular client 285, and the client 285 may include adifferent data agent 295 for each file system. In other cases, a singledata agent 295 processes data for more than one file system.

The operating system 232 can include one or more file system drivers232. The file system drivers 232 can correspond to one or more of thevarious types of file systems that may reside on the client 285. Forinstance, the file system drivers 232 can include a set of one or moreNTFS drivers where an NTFS-based file system resides on the client 285.While shown as residing within the operating system 230, the file systemdrivers 232 reside external to the operating system kernel in certainembodiments, or may reside at least partially within the operatingsystem kernel in other configurations. In cases where some or all of thedata to be restored resides on a non-file system device such as one ormore raw devices, a pseudo device will be created per raw device (e.g.,for each raw device). This raw device approach can be useful whenrestoring files or tables off a large database which resides on one ormore raw devices (e.g., for an Automatic Storage Management[ASM]-capable Oracle database).

As indicated, the system shown in FIG. 2 can be used to create a blocklevel secondary copy 220 of file system data generated by the client285, and then perform a file-level restore of at least a portion of thesecondary copy 220 to the client 285. An example of the block level copyand file level restore will now be described. In the example, thedestination client 285 (the client that the data is being restored to)is the same client computing device 285 that generated the file systemdata contained in the secondary copy 220 (which may be referred to asthe “source client”). In other scenarios, the destination client 285 andthe source client are different.

A primary copy of file system data resides in the information store 290associated with the client computing device 285. For instance, as filesystem objects (e.g., files, directories, mount points, other metadata,etc.) are generated and modified by the applications and othercomponents executing on the client device 285, the primary copy of thefile system information is updated in the information store 290.

The storage manager 250 sends instructions to the client 285 and mediaagent 205 to create a secondary copy of the file system data residing inthe information store 290. For instance, the storage manager 250 mayimplement a backup schedule for the client 285, and send instructions tothe client to perform a backup based on the schedule. In another case,an administrator or other user manually triggers the secondary copy,e.g., via a GUI or other interface.

In response to receiving the instructions, the destination client 285and media agent 205 together work to perform the secondary copy. Forinstance, the data agent 295 processes the file system data for backup,and the data is communicated to the media agent 205. The media agent 205conveys the data to the secondary storage device 215 to create thesecondary copy 220, which represents a version of the file system dataat a particular first point in time, and which resides in the secondarystorage space 216.

As shown, the secondary copy 220 is a block level copy of the filesystem. During a block level copy, the data is broken up into blocks1-N, which may be of a certain fixed size (e.g., several megabytes).These blocks can be referred to as “extents”, and can be created basedon the geometry of the storage device 215, substantially irrespective ofthe file system contents or properties. Each extent can includefragments of files, metadata, and/or unused space. While not shown, thefile system metadata 222 may also be stored on a block (e.g., extent)level basis and therefore correspond to a one or a plurality ofconstituent data blocks. As shown, the secondary copy 220 can begin at aposition 218 in the secondary storage device space 216. While shown asoccupying a contiguous portion of the storage space 216, the file systemcopy 220 can occupy non-contiguous space in the storage device 215 insome other configurations.

As shown, the secondary copy 220 also includes file system metadata 222.The file system metadata 222 generally describes characteristics of thefile system that is represented by the secondary copy 220, and themetadata 222 can include, without limitation, the block size, inodetable location or other information related to inode tables, a blockmap, block group information (e.g., block group size), and the like. Insome cases, such as where the secondary copy is of a Unix based filesystem, some or all of the file system metadata 222 can be included in a“superblock”. The metadata 222 can also describe the file systemdirectory structure here, including parent/child relationships andcontents of individual directories. The file system metadata 222 isorganized according to the specification of the particular file system,and can be used to mount the file system to provide file-level access tothe underlying data, as will be described further.

As shown, the media agent 205 may store a copy 228 of the file systemmetadata using a cache or other storage mechanism. For instance, themedia agent 205 may cache the copy 228 of the file system metadata 222during the backup process.

After the secondary copy 220 is created, a request to restore thesecondary copy 220 to the destination client 285 is received. Or, arequest or instruction is received to mount the secondary copy 220 tothe destination client 285. For instance, an administrator or other usermay interact with a GUI or other interface provided by the storagemanager 250 to browse to a list of one or more secondary copiesassociated with the client 285. The user selects an entry correspondingto the particular secondary copy 220 of the file system datarepresenting the file system of the client 285 at the first point intime. In response, the storage manager 250 instructs the data agent 295on the destination client 285 to begin the restore and/or mount process.

In response to the restore and/or mount instructions, the data agent 295instantiates a device interface 234 on the destination client 285. Thedevice interface 234 provides a mechanism for interfacing thedestination client 285 with the secondary copy 220 of the file systemdata that resides on the secondary storage device 215. The deviceinterface 234 can comprise a device file or special file, and may appearto the operating system 232 as an ordinary file in the file system ofthe client 285. In such cases, instantiating the pseudo device 234 cancomprise writing the device file or special file. The device interface234 in some embodiments allows operating system components such as thefile system drivers 232 to mount the secondary copy 220 of the filesystem, e.g., through the use of standard input/output system calls. Asindicated in FIG. 2, the device interface 234 can be a pseudo-device,such as where the operating system is a UNIX based or UNIX likeoperating system. The pseudo device 234 can generally provide aninterface between the file system driver 232 and the data agent(s) 295.The file system driver 232 requests certain file system blocks from thepseudo device 234, and the data agent 295 pulls the requested blocksfrom secondary storage 215. The pseudo device 234 can also maintain acache of previously retrieved blocks. Thus, in some cases, where thereis a cache hit, certain block requests from the file system driver 232are not actually forwarded to the data agent 295, but are insteadforwarded from the cache of the pseudo device 234 to the file systemdriver 232.

As shown, the device interface 234 can include file system metadata 236and file data 237. In one embodiment, the file system metadata 236(e.g., superblock, directory structure, etc.) and file data 237 arestored in a cache (not shown) that is shared between the pseudo-deviceand the data agent(s) 295. The cache can reside on a disk or otherdedicated storage device. For instance, the file system metadata 236 maybe a copy of or otherwise be derived from the file system metadata 222in the secondary copy 220 that resides on the secondary storage device215. While shown for the purposes of illustration as logically residingwithin the pseudo device 234, the actual data forming the file systemmetadata 236 may reside in the data store 290, or may be stored in othermemory associated with the client (e.g., main memory). In oneembodiment, data agent 295 obtains the cached copy 228 of the filesystem metadata 236 associated with the media agent 205 and associatesit with the pseudo-device 234, e.g., upon instantiation of thepseudo-device 234. The metadata 236 can include file names, fileattributes, file layout information, or any other type of metadata, suchas any of the types of metadata described herein. The pseudo device 234may also include or expose file data 237. In general, the pseudo-device234 can expose all or substantially all of the bytes included in thefile system at the time of the secondary copy 220 (e.g., backup). Thefile data 237 can be a copy of or otherwise be derived from thesecondary copy 220 (e.g., the blocks 1-N) residing in secondary storagedevice 215. While shown for the purposes of illustration as logicallyresiding within the pseudo device 234, the actual data forming the filesystem data 237 may reside in the data store 290, or may be stored inother memory associated with the client (e.g., main memory).

After instantiating the device interface 234, the data agent 295 orother component instructs the operating system 230 to mount thesecondary copy 220 of the file system using the device interface 234.For instance, where the device interface 234 is a device file such as apseudo device, the data agent 234 instructs the operating system 230 tomount the device file. The operating system 232 then accesses the filesystem metadata 236 (e.g., the superblock) to begin the mount process.

For instance, in an example case, the operating system 230 calls amount( ) command, and inputs to the mount( ) command a handle for thepseudo device 234, a temporary directory name, and certain mountoptions. The operating system 230 (e.g., kernel) opens the pseudo-device234 and determines the appropriate file system driver 232. For instance,the operating system 230 accesses the superblock, and based on the filesystem type indicated in the superblock, selects the appropriate filesystem driver(s) 232 to perform the mount. The operating system 230 theninstantiates the selected file system driver 232 on top of the pseudodevice 234 (or otherwise calls the file system driver 232), and passesthe mount request to the file system driver 232. The file system driver232 analyzes the contents of the pseudo device 234 by reading theappropriate blocks, according to the underlying file systemspecification, e.g., by first reading the superblock, which is stored ina pre-determined, known location, and then requesting additional blocksdepending on the contents of the superblock and the structure of thefile system. The additional blocks may generally comprise blockssufficient to retrieve one or more inode tables and a root directoryinode, for example.

As indicated, the superblock can include an identifier that indicates afile system type for the file system represented by the secondary copy220. As an example, the file system type may be NTFS, and the operatingsystem 230 invokes the NTFS drivers to execute the mount. The NTFSdriver(s) begins to process the superblock. In certain embodiments, thefile system metadata 236 includes information sufficient for the NTFSdriver to construct the file system hierarchy. Thus, the NTFS driverprocesses the superblock to create a mounted view of the hierarchy ofthe version of the NTFS file system represented by the secondary copy220. The mounted view can then be displayed to the user. For instance,the view can be presented to the user on a GUI or other interfaceprovided by the storage manager 250.

In general, the pseudo device driver 234 receives the read requests fromthe file system driver 232 and checks its cache to determine whether ornot the requested block is already stored in the cache. If so, itaccesses the block from the cache and forwards the accessed block to thefile system driver 232 to satisfy the request. If the requested block isnot in the cache, the pseudo device driver 234 forwards the request tothe data agent 295 for retrieval from the media agent 205. In someembodiments, the media agent 205 serves blocks having a certainpre-determined (e.g., fixed), relatively large size (e.g., extents of 2,3, 4, 5, 10 or more megabytes) to the data agent 295. On the other hand,the block requests coming from the file system driver 232 are forrelatively small blocks (e.g., between 1 and 10 kilobytes, less than 10kilobytes, less than 100 kilobytes, or less than 1 megabyte). As aresult, the cache shared by the pseudo device driver 234 and the dataagent 295 can fill up rather quickly, because the data agent 295 isreceiving rather large amounts of data in response to requests from thefile system driver 232 for relatively small amounts of data. The initialmount process is intended to create a mounted view of the file system,which generally only involves accessing and processing file systemmetadata 236, not file data 237. However, as indicated, the media agent205 will forward extent-level data to the data agent 295, and eachextent can include both file data 237 and file system metadata 236.Thus, it is likely that file data 237 will be forwarded to the dataagent 295 during the mount process, along with the requested file systemmetadata 236. For instance, file level data 237, although notspecifically requested by the file system driver 232, may be included inan extent forwarded by the media agent 205 that includes requested filesystem metadata 236.

Through the use of the pseudo device 234, the system advantageouslyexploits the existing NTFS driver 232 to interpret the file systemmetadata 236 and create the mounted view of the file system hierarchy.Otherwise, customized code may be required for each supported filesystem type and/or version in order to properly process the file systemmetadata, according to the specification of the particular type of filesystem.

Once the file system represented by the secondary copy 220 is mounted onthe destination client 285 and viewable to the user, the user can selecta subset (e.g., one or more files or directories) of the file system torestore to the destination client 285. In the example scenario, the userselects FILE A and FILE B to restore. In response, a restore applicationor module running on the destination client (or another appropriatecomponent such as one of the data agents 295) may use a standard I/Osystem call to request the mounted files. The file system driver 232 inturn requests any missing blocks for the requested files from the pseudodevice 234, which either (1) satisfies the requests from its cache or(2) for requests which do not produce a cache-hit, forwards the requestto the data agent 295 for delivery to the media agent 205. In certainembodiments, the request sent from the pseudo device 234 to the dataagent 295 is at the extent-level, and is thus for the extent(s)including requested data block(s), not the for the individual datablocks requested by the file system driver 232. The media agent 205 inturn accesses the extent(s) including the appropriate data blocks fromthe secondary storage device 215, and returns the extent(s) to the dataagent 295, via the restore data pipeline. The system maintains a mappingthat maps the extents in the recovered file system to the actualphysical locations of the extents on the secondary storage device 215.For instance, the mapping may reside on the media agent 205 in somecases. In such cases, the pseudo device 234 communicates logicalidentifiers for the requested extents to the media agent 205, and themedia agent 205 accesses a stored mapping to identify the physicallocations on the secondary storage device 220 at which the extents orother types of data blocks reside. In an alternative embodiment, thepseudo device 234 maintains such a mapping. In this case, the pseudodevice 234 receives block requests from the file system driver(s) 232including logical data block identifiers. The pseudo device 234 uses themapping to translate the logical identifiers to physical data blocklocations on the secondary storage device 215, and communicates thephysical data block locations to the media agent 205. The pseudo device234 passes the data blocks along to the file NTFS system driver(s) 232,and the files are eventually reconstructed and restored to theinformation store 290. In some cases, the files are copied to atemporary mount point and are then copied to the information store 290or to another selected location.

FIG. 3 is flow diagram illustrating an example routine 300 forperforming a file level restore from a block level secondary copy 220.The routine 300 is described with respect to the system of FIG. 2.However, one or more of the steps of routine 300 may be implemented byother data storage systems, such as those described in greater detailabove with reference to FIGS. 1A-1E. The routine 300 can be implementedby any one, or a combination of, a client, a storage manager, a dataagent, a media agent, and the like. Moreover, further details regardingcertain aspects of at least some of steps of the routine 300 aredescribed in greater detail above, e.g., with reference to FIG. 2.

At block 302, the routine 300 receives a request to perform a file levelrestore of a block level secondary copy 220 stored in one or moresecondary storage devices 215. For instance, a user may interact with aGUI hosted by the storage manager 250 or another component to select theblock level secondary copy 220, by clicking on an icon representing thesecondary copy 220, for example. In response, the storage manager 250sends a request or instructions to the data agent 295 residing on thedestination client 285 to mount the secondary copy 220.

At block 304, in response to receiving the request to mount thesecondary copy 220, the data agent 295 instantiates a device interface234 on the destination client 285. The device interface 234 provides amechanism for the operating system 230 to mount and access the secondarycopy 220. For instance, as described above, the device interface 234 maybe a pseudo device, device file, special file, combination of the sameor the like. The pseudo device 234 can also include file system metadata236, such as a superblock associated with the file system represented bythe secondary copy 220.

The data agent 295 instructs the operating system 230 to use the deviceinterface 234 to mount the secondary copy 220 at step 306. For instance,where the device interface 234 comprises a pseudo device, the data agent295 instructs the operating system 230 to mount the pseudo device 234.The operating system 230 mounts the pseudo device 234 by accessing andbeginning to process the file system metadata 236 embedded in orobtainable via the device interface 234. For instance, the metadata 236may include information identifying the type of file system representedby the secondary copy 220, and the operating system 230 selects anappropriate file system driver(s) 232 to perform the mounting based onthe file system type. The selected file system driver(s) 232 continuesto process the file system metadata 236 to construct a navigable view ofthe file system, which can be displayed to the user.

The user may then navigate the view of the mounted file systemrepresented by the secondary copy 220, and selects one or more files torestore from the secondary copy 220. A restore application or othermodule executing on the destination client 285 copies the selectedfiles, e.g., via standard operating system I/O calls. As part of thisprocess, the file system driver(s) 232 process the file system metadata236 to identify data blocks corresponding to the requested files, andrequests the data blocks via the device interface 234. At block 308, thedevice interface 234 and media agent 205 service the block requests. Forinstance, the device interface 234 communicates the data block requests(e.g., for extents including desired data blocks) to the media agent 205via the data agent 295, which accesses the requested data blocks (e.g.,extents) from the secondary storage device 215. The media agent 205returns the accessed data blocks (e.g., extents) to the data agent 295,which stores them in a cache stored with the device interface 234. Thedata agent 295 can also indicate to the pseudo device 234 that therequested extent has been successfully obtained, and the pseudo device234 in turn forwards it along to the file system driver(s) 232. The filesystem driver(s) 232 and/or another component reconstitute the requestedfile(s) using the received data blocks and, at block 310, the file(s)are restored to primary storage. For instance, the recovered files arestored in the information store 290.

Terminology

Conditional language, such as, among others, “can,” “could,” “might,” or“may,” unless specifically stated otherwise, or otherwise understoodwithin the context as used, is generally intended to convey that certainembodiments include, while other embodiments do not include, certainfeatures, elements and/or steps. Thus, such conditional language is notgenerally intended to imply that features, elements and/or steps are inany way required for one or more embodiments or that one or moreembodiments necessarily include logic for deciding, with or without userinput or prompting, whether these features, elements and/or steps areincluded or are to be performed in any particular embodiment.

Depending on the embodiment, certain acts, events, or functions of anyof the algorithms described herein can be performed in a differentsequence, can be added, merged, or left out all together (e.g., not alldescribed acts or events are necessary for the practice of thealgorithms). Moreover, in certain embodiments, acts or events can beperformed concurrently, e.g., through multi-threaded processing,interrupt processing, or multiple processors or processor cores or onother parallel architectures, rather than sequentially.

Systems and modules described herein may comprise software, firmware,hardware, or any combination(s) of software, firmware, or hardwaresuitable for the purposes described herein. Software and other modulesmay reside on servers, workstations, personal computers, computerizedtablets, PDAs, and other devices suitable for the purposes describedherein. Software and other modules may be accessible via local memory,via a network, via a browser, or via other means suitable for thepurposes described herein. Data structures described herein may comprisecomputer files, variables, programming arrays, programming structures,or any electronic information storage schemes or methods, or anycombinations thereof, suitable for the purposes described herein. Userinterface elements described herein may comprise elements from graphicaluser interfaces, command line interfaces, and other suitable interfaces.

Further, the processing of the various components of the illustratedsystems can be distributed across multiple machines, networks, and othercomputing resources. In addition, two or more components of a system canbe combined into fewer components. Various components of the illustratedsystems can be implemented in one or more virtual machines, rather thanin dedicated computer hardware systems. Likewise, the data repositoriesshown can represent physical and/or logical data storage, including, forexample, storage area networks or other distributed storage systems.Moreover, in some embodiments the connections between the componentsshown represent possible paths of data flow, rather than actualconnections between hardware. While some examples of possibleconnections are shown, any of the subset of the components shown cancommunicate with any other subset of components in variousimplementations.

Embodiments are also described above with reference to flow chartillustrations and/or block diagrams of methods, apparatus (systems) andcomputer program products. Each block of the flow chart illustrationsand/or block diagrams, and combinations of blocks in the flow chartillustrations and/or block diagrams, may be implemented by computerprogram instructions. Such instructions may be provided to a processorof a general purpose computer, special purpose computer, or otherprogrammable data processing apparatus to produce a machine, such thatthe instructions, which execute via the processor of the computer orother programmable data processing apparatus, create means forimplementing the acts specified in the flow chart and/or block diagramblock or blocks.

These computer program instructions may also be stored in acomputer-readable memory that can direct a computer or otherprogrammable data processing apparatus to operate in a particularmanner, such that the instructions stored in the computer-readablememory produce an article of manufacture including instruction meanswhich implement the acts specified in the flow chart and/or blockdiagram block or blocks. The computer program instructions may also beloaded onto a computer or other programmable data processing apparatusto cause a series of operations to be performed on the computer or otherprogrammable apparatus to produce a computer implemented process suchthat the instructions which execute on the computer or otherprogrammable apparatus provide steps for implementing the acts specifiedin the flow chart and/or block diagram block or blocks.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the disclosure. Indeed, the novel methods and systems describedherein may be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the describedmethods and systems may be made without departing from the spirit of thedisclosure. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the disclosure.

The invention claimed is:
 1. A method for performing a file levelrestore of a block level secondary copy in a data storage system,comprising: instantiating a device node on a first computing device, thedevice node providing an interface for a file system driver executing onthe first computing device to access a block-level secondary copy offile system data which resides in secondary storage; with the filesystem driver, interfacing with the device node to obtain file systemmetadata corresponding to the block-level secondary copy; processing theobtained file system metadata to mount the block-level secondary copyonto the first computing device; in response to a request to access atleast one file of the mounted secondary copy, interfacing with thedevice node to request a read of the at least one file; with the devicenode and in response to the read request, initiating retrieval of the atleast one file from secondary storage; and copying the retrieved atleast one file to primary storage associated with the first computingdevice.
 2. The method of claim 1, wherein the device node comprises oneor more of a pseudo device, a device file, or a special file.
 3. Themethod of claim 1, wherein said interfacing with the device node torequest a read of the at least one file comprises making a standardsystem read call.
 4. The method of claim 1, wherein a media agent moduleexecuting on a second computing device and in communication with thesecondary storage retrieves a data block including the at least one fileand forwards the data block to a data agent module executing on thefirst computing device.
 5. The method of claim 1, wherein the filesystem metadata specifies at least a directory structure for theblock-level secondary copy.
 6. The method of claim 1, wherein the filesystem metadata includes a superblock and said processing comprisesprocessing the superblock.
 7. The method of claim 1, wherein the filesystem driver corresponds to a first file system type and wherein thefile system data of the block-level secondary copy is of the first filesystem type.
 8. The method of claim 1, wherein the request to access theat least one file is a restore request entered by a user via a graphicaluser interface.
 9. The method of claim 1, wherein the retrieved at leastone file is included in a data block that also includes at least onesecond file of the mounted secondary copy, the method furthercomprising: maintaining the data block in a cache associated with thefirst computing device; receiving a request to access the at least onesecond file in the mounted secondary copy; with the file system driverand in response to the request to access the at least one second file,interfacing with the device node to request a read of the at least onesecond file; with the device node, determining that the at least onesecond file resides in the cache; retrieving the at least one secondfile from the cache; and copying the at least one second file to theprimary storage.
 10. A data storage system, comprising: a firstcomputing device; a data agent module executing on the first computingdevice, the data agent module configured to instantiate a device node onthe first computing device, the device node providing a file systemdriver executing on the first computing device with an interface toaccess a block-level secondary copy of file system data which resides insecondary storage, wherein the file system driver is configured tointerface with the device node obtain file system metadata correspondingto the block-level secondary copy and to process the obtained filesystem metadata to mount the block-level secondary copy onto the firstcomputing device; wherein the data agent module is further configuredto: in response to instructions from the device node to retrieve atleast one file of the mounted block-level secondary copy from secondarystorage, request the at least one file from secondary storage; andreceive the at least one file from secondary storage; and wherein thereceived at least one file is copied to primary storage associated withthe first computing device.
 11. The data storage system of claim 10,wherein the device node comprises one or more of a pseudo device, adevice file, or a special file.
 12. The data storage system of claim 10,wherein the device node generates the request to retrieve the at leastone file in response to the file system driver making a standard systemread call for the at least one file.
 13. The data storage system ofclaim 10, wherein a media agent module in communication with thesecondary storage responds to the request from the data agent module toretrieve a data block including the at least one file, and forwards thedata block to the data agent module.
 14. The data storage system ofclaim 10, wherein the file system metadata specifies at least adirectory structure for the block-level secondary copy.
 15. The datastorage system of claim 10, wherein the file system metadata includes asuperblock and the file system driver processes the superblock to mountthe block-level secondary copy.
 16. The data storage system of claim 10,wherein the file system driver corresponds to a first file system typeand wherein the file system data of the block-level secondary copy is ofthe first file system type.